Keihin Carburetor Parts family 3,4,5

April 3, 2021

== carb ID# ============  M O P E D S  ===========
3. PA 00A-A  1973-77 Honda PC50K1, PF50R ooo 50 kmh OHV
3. PA 01A-A  1973-77 Honda PC50K1, PF50R ooo 40 kmh OHV
3. PA M0A-A  1978-83 Indian AMI50 4-Stroke xx  30 mph OHV
4. BB 21A-B  1978-78 Honda PA50-I Hobbit xxx   20 mph TS
4. BB 21A-F  1979-79 Honda PA50-I Hobbit xxx   20 mph TS
4. BB 20A-C  1978-78 Honda PA50-II Hobbit xx    30 mph TS
4. BB 20A-F  1979-83 Honda PA50-II Hobbit xx    30 mph TS
5. P 006A-A  1974-75 Honda MR50 Elsinore xxx   40 kmh OHC
5. PA 06A-A  1973-78 Honda PM50, PF50M xxxx   40 kmh TS
5. PA 07A-A  1975-78 Honda PF50M xxxxxxxxx    50 kmh TS

 

 

 

 

 


1973-78 Honda PF50 Amigo,
Amigo-R, Novio-R  40-50 kph

3. Keihin
size   carb   years  model code   models00xx   speed version
0∅9 PA 01A 1973-77 081 Honda PC50K1 00xxxxxx  40 km/h
0∅9 PA 01A 1973-78 099 Honda PF50 Amigo/Novio 40 km/h
∅10 PA 00A 1973-77 081 Honda PC50K1 00xxxxxx  50 km/h
∅10 PA 00A 1973-78 099 Honda PF50 Amigo/Novio 50 km/h
∅10 PA M0A 1978-83 000 Indian AMI-50 (US) xxxx   30 mph

1973 Honda PC50K1

1980 Indian AMI-50 (US)

 

 

 

 

 

 

 

 

 

1975 Honda PC50K1

1980 Indian AMI-50 (US)

Keihin PA-00A carb

Missing the jet pad #1e.

 

 

 

 

 

 

 

 

#0  16100-081-024 Keihin PA-00A carb

#0  Keihin PA-M0A carb

 

 

 

 

 

 

 

 

Late PC50: In 1973 the PC50 carburetor changed from “donut” float to a swinging float, and a NC50-type float bowl and gasket. The 1973-77 PC50K1 and 1973-78 PF50 engine and carb are the same as the Taiwan remake engine and Keihin carburetor used on the 1978-83 Indian moped. So the carburetor parts are the same also, with some exceptions.

PA 00A (16100-081-024) and PA 01A (16100-099-693) have the same parts. The push-in jet size, venturi size and intake flange o-ring are the only difference. 

PA M0A (E210-20-50) has the same parts as PA 00A and PA 01A, except for 1) a screw-in jet instead of push-in, 2) no jet pad, 3) no jet pad holder in float bowl, 4) a white regular type float instead of a black stirrup type. 

Flange Mount: 32 mm hole spacing, 2 x 18 (22 od) o-ring 00A, 01A.

Indian AMI50: The Indian AMI50 Chief four stroke moped engine, OHV with pushrods and internal pedals, made from 1978-1984, is a Taiwan-made copy of a Honda PC50K1 or PF50 engine, OHV with pushrods and internal pedals, made from 1973-1978. The Indian had three different carburetors, Tillotson (some 1978), Keihin (some 1978, most 1979-80), Mikuni (some 1980, all 1981-84). Only the Keihin parts are listed here.

#1  16100-081-004
for PA 00A and 01A

#1  16010-143-305
for PA 00A 01A 03A

#1  16010-081-014
for PA M0A

#1  16010-181-305
for PA M0A 03C/D/E/F

 

 

 

 

 

 

 

 

 

Keihin PA 00A, PA 01A, PA M0A

quantity
o#
⇓⇓⇓   
Keihin  (a)PA-00A  (b)PA-01A  (c)PA-M0A
o# abc price Indian part#  Honda part#    description        specs
0
0 1oo  N/A 0000-00-00 16100-081-024 carburetor PA 00A Ø10 E10
00 o1o  N/A 0000-00-00 16100-099-693 carburetor PA 01A   Ø9 E10
00 oo1  N/AE210-00-50 16100-000-000 carburetor PA M0A Ø10
o1 11o $22 0000-00-00 16010-081-004 gasket solo-set   1a o d e f o h i
o1 110 $23 0000-00-00 16010-143-305 gasket multi-set 1a c d e f o h i
o1 oo$18 E231-gasks  16010-081-014 gasket solo-set   1a o o o f g h
o1 001 $19 E231-gasm  16010-181-305 gasket multi-set 1a o o o f g h i  l
1a 111 $$3 E231-####00000-000-000 top rubber washer 10 x 18 x 1
1c 000 $$2 E231-####00000-000-000 intake o-ring 2 x 20 (24 od) 
1d 11o 0$2 0000-00-00 16176-551-004 main jet o-ring 1 x 3 (5 od)
1e 11o $10 E231-####16197-063-004 jet pad disk Ø7.5 x 1.8 
1f  111 $15 E231-02-00 00000-000-000 float bowl gasket Ø1.5 NC50-type
1g oo$$2 E231-11-00 00000-000-000 drain screw o-ring 1.5 x 4 (7 od)
1h 11o $$2 0000-00-00 00000-000-000 intake o-ring 2 x 18 (22 od)
1i  110 0$2 0000-00-00 16175-260-004 drain screw o-ring 2 x 2.5 (6.5 od)
02 111 $24 E231-13-00 16155-883-005 float needle valve non-stirrup type
03 111  N/A E231-####16012-081-014 needle set 3a 3b 3c 3d
3a 111 $10 E231-09-00 00000-000-000 jet needle D348 thick Ø2 x 33
3b 111 0$2 E231-10-00 16157-044-004 needle e-clip substitute 1.5mm
3c 111 0$5 E231-08-00 16156-044-004 w-spring clip
3d 111  N/A E231-####16133-081-004 needle jet ∅3.95 ∅5 ∅3.9 ∅5 x 27
3d ooo 0$6 0000-00-00 ooooo-000 03A needle jet ∅3.95 ∅5 ∅3.9 ∅5 x 27
3d ooo 0$6 0000-00-00 ooooo-000 03B needle jet ∅3.95 ∅5 ∅3.9 ∅5 x 27
o4 110  N/A E231-####16013-099-691 float set black 4c 4d 4e PA 00A, 01A
4a 001 $28 E231-####16013-147-004 float set white 4b 4d 4e PA M0A
4b 001 $21 E231-06-00 00000-000-000 float bare white non-stirrup
4c 110  N/A E231-06-00 00000-000-000 float bare black stirrup
4d 111 $$4 E231-15-00 00000-000-000 hinge pin substitute Ø2 x 18.5
4e 111 $$3 E231-16-00 0-93600-04006 hinge pin screw M4 x 6 sunk
05 111 $30 E231-01-00 16014-081-004 top set 5a 5b 1a
5a 111 $23 E231-03-00 00000-000-000 substitute cap brass M20-1.0
5b 111 0$3 E231-####00000-000-000 cable adjuster male M6-0.75
06 11oN/A E231-01-00 16015-081-004 chamber set 6a 6b 1f 1i
6a 11oN/A 0000-00-00 16015-165-B10 float bowl bare for push-in jet
06 oo1 $67 E231-####16015-099-601 chamber set 6a 6c 1f 1g
6a oo1 $46 E231-01-00 16015-165-B10 float bowl bare for screw-in jet
6b 11o  N/A 0000-00-00 00000-000-000 bowl drain screw M4-0.70
6c oo1 $16 E231-23-00 00000-000-000 bowl drain screw M6-1.00
07 111 $15 E231-####16016-143-620 adjustment screw set 7a 7b 7c 7d
7a 111 $$6 E231-19-00 00000-000-000 idle air mix screw M6-0.75 special
7b 111 $$4 E231-21-00 00000-000-000 idle speed screw M4-0.70 special
7c 111 $$7 E231-20-00 00000-000-000 idle air screw spring Ø5.6 x 10
7d 111 $$2 E231-22-00 00000-000-000 idle speed screw spring Ø4.9 x 9
08 1o1 $34 E231-####16022-081-004 valve set 8a 8b Ø13 PA 00A
08 1o1 $00 E231-####16022-HB2-003 new #
8a 1o$22 E231-07-00 00000-000-000 throttle slide Ø13 #15A PA 00A
8b 1o$12 E231-17-00 00000-000-000 throttle spring Ø10 x 42 PA 00A
08 o1oN/A 0000-00-00 16022-143-620 valve set 8a 8b Ø12 PA 01A
08 o10 $00 0000-00-00 16022-191-004 new #
11 111 0$2 E231-04-00 16118-086-004 rubber boot substitute Dellorto
12 222 0$1 E231-12-00  93500 – 04012 bowl screw M4 x 12 pan phillips
13 222  .25 E231-####   95002-02070 bowl screw lock washer
14 111  N/A E231-####   95001-35150 drain hose
15 111  N/A E231-####0-95002-02070 drain hose clamp
16 oo1 $$7 E231-18-00 99101-187-070 main jet #70 M6-0.75 screw-in
16 oo1  N/A E231-18-00 99201-187-0700 new #
16 11o $16 0000-00-00 99201-081-070 main jet #70 0.0275″ push-in
16 11o  N/A 0000-00-00 99201-081-0700 new #
17 oo1  N/A E231-01-00 00000-000-000 carb body bare
18 oo1  N/A E231-####00000-000-000 idle jet press-in tube 0.38 mm=0.015″

Indian PA MOA carb disassembled

 

Choke plate: These three carbs have a lever choke that swings a plate to block air flow. There is no enrichment fuel path or jet. So the float bowl has no choke jet. The other baby Keihins with cable or vacuum operated choke do have a choke jets in their float bowls. The choke (enrichment) fuel passes up through the sealed off corner of the bowl gasket.  

Float Bowl: The PA-03A and 03B chamber set (float bowl, float bowl gasket, drain screw and drain screw o-ring) from 1970’s Honda mini-cycles (Mini Trail or Monkey) interchanges with a PA 00A, 01A chamber set  from 1970’s Honda mopeds. The drain screw (4 or 6 mm) and its o-ring (2×2.5 or 1.5×4) are different. So if the float bowl is changed the drain screw must also be changed. 

Needle jet: The PA-03A and 03B mini-cycle needle jets (emulsion tubes) interchange with PA 00A, 01A, and M0A moped ones. These press out with taps from a hammer and punch from above. At first the punch tip needs to be bigger than the 4 mm tube end. Once the tube end gets below the floor a smaller 3.5 to 3.9 mm straight round bar is needed. It has to enter the 4 mm hole and contact the idle tube around the edge.

Keihin MOA parts

Idle jet: A little downstream from the needle jet is the idle jet. It is a pinhole 0.015″ at the upper end of a vertical brass tube about 20mm long. The idle tube is a press fit in the carb body. Some can be pulled out with just a pliers. Some might be tighter and require a drill bit be placed inside the tube to prevent crushing from the tighter pliers grip. This tube was never intended to be replaced and is not sold or included in any common carb kit. 

Air tunnels: In the front below the main air inlet are two small horizontal air tunnels. The center tunnel is main air and the side tunnel is idle air. The small amount of air sucked in through the main air tunnel passes through tiny holes in the emulsion tube and becomes thousands of microscopic air bubbles in the liquid gasoline that is being drawn upward. The tiny amount of air sucked in through the idle air tunnel passes around the idle air adjustment screw cone shape tip and goes to the vertical idle passage just above the idle jet. The idle air tunnel is the size of a regular paper clip 0.036 inch. A straightened paper clip cleans it perfectly.    

 


PA50 speed versions

4. Keihin
∅10 BB 21A-B #148 on 1978-78 Honda PA50 I  Hobbit (US) 20 mph
∅10 BB 21A-F #148 on 1979-79 Honda PA50 I  Hobbit (US) 20 mph
∅12 BB 20A-C #148 on 1978-83 Honda PA50 II Hobbit (US) 30 mph

1978 PA50II 30mph

1978 PA50I 20mph

1983 Honda PA50II

 

 

 

 

 

 

 

 

#0 16100-148-645  Keihin BB 21A-B

#0  16100-148-646 Keihin BB21A-F

 

 

 

 

 

 

 

 

 

#0  16100-148-708  Keihin BB 20A-C

 

 

 

 

 

 

 

 

Flange mount: 42 mm bolt hole spacing

Honda’s successor to the four-stroke PC50 was the two-stroke PA50, known in the USA as Hobbit, and in Europe as Camino. It was made in Belgium by Honda Benelux, so it had a mix of Japanese and European design and componentry. 

In US models, 20 mph versions were 1978-79 red. 30 mph versions were 1978-79 yellow, 1980 yellow, 1981-82 red, and 1983 black.

This Keihin BB type carburetor is not like any other moped carburetor. It looks more like a Honda generator carburetor. It is a very flat design. It has to be special because it swings up and down with the engine, and is very close to the frame at the place where you step through.  The BB type floats on PA50 are wider and flatter than NC50 or Z50 floats.  

#1  16010-124-760

#1  16010-156-305

 

 

 

 

 

 

 

 

Keihin (1978-83 Honda PA50) carburetor illustration

Keihin BB-20A and BB-21A

  quantity
o#
⇓⇓⇓⇓ 
(a)BB 21A-B (b)BB 21A-F (c)BB 20A-C (d)BB 20A-F? 
o# abcd price  Honda part# x description xxx specs
00 1o00  N/A
16100-148-645 carburetor 21A-B ∅10 20 mph 1978 
00 01o0  N/A
16100-148-646 carburetor 21A-F ∅10 20 mph 1979
00 o010  N/A
16100-148-708 carburetor 20A-C ∅12 30mph 1978
00 o001  N/A
16100-148-708 carburetor 20A-F ∅12 30mph’79-83 
01 1111 $14 16010-124-760
gasket solo-set   1c 1g oo 1j
01 1111 $15
 16010-156-305 gasket multi-set 1c 1g 1h 1j
1c 1111 $$2 00000-000-000 intake o-ring 2 x 20 (24 od)
1g 1111 $$2 00000-000-000 drain screw o-ring 1.5 x 4 (7 od)

1j  1111 $11 00000-000-000 float bowl gasket 2 x 50 (54 od)
o2 1010  N/A 16011-147-004  16011-147-305
o2 1010 $21 16011-881-741 float needle stirrup type
o2 010$24 16011-883-005 float needle regular type

03 1010  N/A 16013-124-760
03 1010  N/A 16013-124-762 float set black 3a 3c 21A-B, 20A-C
03 010 N/A 16013-883-305 float set white 3b 3c 21A-F, 20A-F?

3a 1010  N/A 00000-000-000 float bare black stirrup type
3b 010
1  N/A 00000-000-000 float bare white regular type
3c 1111  N/A 00000-000-000 hinge pin ∅2 x 23
04 1111  N/A 16016-148-611 screw set

04 1111  N/A 16016-890-015 screw set 4a 4b 4c 4d 4e
4a 1111 0$1 00000-000-000 idle speed screw M4 x 15 slot
4b 1111  N/A 00000-000-000 idle speed spring
4c 1111  N/A 00000-000-000 idle fuel screw
4d 1111  N/A 00000-000-000 idle fuel spring
4e 1111 0$3 00000-000-000 cleaning access plug M5 x 5 slot
05 1111  N/A 16024-124-760 drain screw set
07 1111  N/A 16110-148-010 choke lever cover
08 1111  N/A 16166-148-740 nozzle, main
09 1111  N/A 16199-148-611 vent hose ∅3.5 ∅6.5 x 65 gray
09 1111 
.50 16199-148-sub substitute  ∅3.1 ∅6.3 x 65 clear
10 1111 0$2 0-93500-04008 cable pinch screw M4 x 8
11 2222 0$1 0-93500-04012 bowl screw M4x12 pan phillips
12 2222  .50 0-94111-04800 lock washer M4 split
13 1111  N/A
95001-35400-40 drain hose ∅3.5 ∅7.0 x 400 gray
13 1111 0$1 95001-35400sub substitute ∅3.1 ∅6.3 x 400 clear
14 1010 0$7 99101-124-600 main jet 60 21A
14 0101 0$7 99101-124-780 main jet 78 20A

15 1111  N/A 0-95002-02070 drain hose clamp B7 (for 7 not 6.3)
16 1111  N/A 0-95002-02065 vent hose clamp B6.5

 

1978 PA50 carb service

PA50 carb removal

 Servicing: The best way to remove the PA50 carburetor is to hold the back of the bike up by either a rope tied to an overhead beam, or with a milk crate and blocks of wood. Remove the floorboards and side covers. Unplug the ignition wires from the coil at the right rear. Pull them through and move them out of the way. Disconnect the decompression cable and the spark plug cap. Loosen the wiring clamps so there is slack in the wires. Remove the lower rear shock bolts and the swing arm pivot bolt above the engine. Then the whole sub-frame can be moved away from the main frame, either by lifting the back of the bike up, or by swinging it around sideways.

Note that the float bowl can go on two different ways. The wrong way assembles normally, but causes the vertical brass overflow tube to contact the float. Honda designed all of the cleaning ports, drain screws, and adjustment screws to face the right side of the bike, which is the upper left in the exploded view. The drain hose spigot on the float bowl faces the same way as the adjustment screws. The other way to tell is by shaking the carburetor. If you can hear the float rattling inside then the float is not stuck so the float bowl is on correctly. 

While every other moped carburetor is a sliding throttle valve type, this one is a swinging plate throttle valve. The reason is to be flatter, to get more clearance from the bottom of the frame. The manual choke is also a swinging plate, with an automatic release.

Some servicing can be done with the carburetor installed. It is easy to clean the idle passages and jet by spraying a one second long burst of carb spray into the idle mixture screw hole, followed by compressed air. The running engine is allowed to consume the flammable solvent before the next burst is sprayed in, to prevent the engine from getting flooded.

 

 


1975-78 PF50M

5. Keihin
size carb model code years       Honda models
∅12   006A on #131 1974-75 MR50 Elsinore (US)
∅10 PA06A on #122 1973-75 PM50 Canguro, PM50 Novio  40 km/h
∅10 PA07A on #143 1975-78 PF50M, PF50MR (BE,NL,NZ) 40 km/h
∅12 PA07A on #143 1975-78 PF50M, PF50MR (FR,UK,CA) 50 km/h

1973 Honda PM50 Canguro

1974 Honda PM50 Novio

 

 

 

 

 

 

 

 

 

#0 16100-131-004 Keihin 006A

#0  16100-122-024 PA06B

#0  16100-143-620 Keihin PA07A

 

 

 

 

 

 

 

 

Flange mount: PA06A PA07A 32 mm bolt hole spacing
Spigot-mount: 006A

Cable-choke: The choke cable passes through the carb top along with the throttle cable.  

Float: These carbs have a black float 16003-114-004 but a non-stirrup type float needle. The float needle and seat are sold as a set 16011-122-004.

#1  16010-131-004

#1  16010-122-305

 

 

 

 

 

 

 

Keihin PA06A-A and PA07A-A

  quantity
o#
⇓⇓⇓   
Keihin    (a)006A   (b)PA06A   (c)PA07A
o# abc price  Honda part# x description xxx specs 
00 10o  N/A 16100-131-004 carburetor ∅12 006A   74-75 MR50
00 o00  N/A 16100-122-004
00 o00  N/A 16100-122-014 carburetor ∅10 696A
00 o00  N/A 16100-122-024 carburetor ∅10 PA06B
00 01o  N/A 16100-122-690 carburetor ∅10 PA06A PM50 < 20101
00 01o  N/A 16100-122-691 carburetor ∅10 PA06A PM50 > 20100
00 01o  N/A 16100-122-692 carburetor ∅10 PA06A PM50 > 20100
00 o01  N/A 16100-143-620 carburetor ∅12 PA07A PF50M, PF50MR
00 10o  N/A 16010-131-004 gasket solo-set   5-piece 1a d e f o i
01 011  N/A 16010-122-004 16010-122-014
01 011  N/A 16010-122-305 gasket multi-set 7-piece 1a d e f h i s
1a 111  N/A 00000-000-000 top gasket Ø1.5
1d 111 0$2 16176-551-004 main jet o-ring 1 x 3 (5 od)
1e 111 $10 16197-063-004 jet pad disk Ø7.5 x 1.8 
1f  111  N/A 00000-000-000 float bowl gasket Ø1.5
1h 011 $$2 00000-000-000 intake o-ring 2 x 18 (22 od)
1i  111 0$2 16175-260-004 drain screw o-ring 2×2.5(6.5od)
1s 111  N/A 00000-000-000 float valve o-ring 1.5 x 5 (8od)
96 011  N/A 99201-122-0650 main jet push-in #65 PA06A
96 100  N/A 99201-122-0750 main jet push-in #75 006A PA07A?

 

 

 


Keihin Carburetor Parts family 1, 2

April 3, 2021

== carb ID# ============  M O P E D S  ===========
1.
50A, 50B1966-68 Honda P50 xxxxxxxxxxxx  40 kmh OHC
1. 610 (50B) 1967-68 Honda P50 Little Honda     40 kmh OHC
2. C4B, C5B   1969-70 Honda PC50A xxxxxxx  40,50 kmh OHC
2. C5A, C5A1969-70 Honda PC50 Little Honda   40 kmh OHC
2. S4A, S5A   1969-70 Honda PS50  xxxxooo x 40,50 kmh OHC
2. F4A, F5A   1970-73 Honda PC50K1, PF50 x40,50 kmh OHV
2. S4B, S5B   1970-71 Honda PS50  xxxxxxxxooo50 kmh OHV
 

 

 

 

 


1. Keihin 
carb model code years  frame number range      models
50A-000 #044 1966-67 P25-A000001-00000 Honda P25
50A-610 #044 1967-68 P50-100001-148606 Honda P50
50A-610 #044 1967-68 P50-100001-148606 Honda P50 Little Honda (US)
50B-NL   #044 1967-68 P50-128651-148606 Honda P50 (Netherlands)

50B-000 #044 1968-68 P50-148607-000000 Honda P50

50B-000 #044 1968-68 P50-148607-000000 Honda P50 Little Honda (US)

1964 P25 (NL model)

1967 Honda P50

1968 P50 (US model)

 

 

 

 

 

 

 

Bore:  42.0 mm, stroke 35.6 mm, displacement: 49.3 cc. P50’s have down-draft carburetors, unusual.
50B carbs do not have a replaceable float valve. It’s part of, and only sold with, the float chamber cover.
50B has a larger carb size ∅11? and  jet #68 or 62. 50A has a smaller carb size ∅9? and jet #60 or 55.

#0  16010-044-004

#1  16010-044-680

 

 

 

 

 

 

 

 

Honda P50 carburetors

  =00 quantity   Keihin
0#=00
⇓⇓⇓⇓   
(a)50A(b)50A-610  (c)50B-N  (d)50B

0#=00 abcd  price   Honda part#   description        specs
00=00 1000N/A 16100-044-030
00=00 1000N/A 16100-044-315 carburetor 50A-000 ’66-67
00=00 0100N/A 16100-044-405 carburetor 50A-610 ’67-68
00=00 1100N/A 16010-044-004 gasket set 10-piece 4 12 13
00=00 1100  N/A 16010-044-004 15 20 20 20 24 27 32
00=00 1100N/A 16151-044-681 jet needle
11=00 1100N/A 16125-044-004 float valve set
12=00 1100N/A 16173-001-004 rubber seal ring
13=00 1100N/A 16188-044-004 valve fiber washer 7.2 x 10.5
16=00 1000N/A 16133-044-004 needle jet
16=00 0100  N/A 16133-044-681 needle jet 2.6 x 1.55
17=00 1000N/A 0-99144-03804 slow jet 38
17=00 0100N/A 0-99144-03504 slow jet 35
24=00 1100N/A 16123-044-004 jet access gasket
25=00 1000N/A 0-99120-06014 main jet 60
25=00 0100N/A 0-99120-05514 main jet 55
26=00 1100N/A 16112-044-004 float chamber cover
30=00 4400 0$1 0-93600-04008 sunk-phillips screw M4 x 8
32=00 1100N/A (not sold separately) choke shaft o-ring
=======================================
00=00 0010N/A 16100-044-681 carburetor 50B-NL ’67-68
00=00 0001  N/A 16100-044-683 carburetor 50B-00 1968
01=00 0011 $18 16010-044-680 gasket set 4-piece 4 15 20 27
1n=27 1111 0$6 16174-044-004 float o-ring 1.25 x 38 (40.5od)
1p=04 1111 0$5 16171-044-004 top rubber washer 10 x 15 x 1
1r=15 1111 0$5 16175-001-004 needle jet o-ring  2 x 4 (8od)
1i =20 3333 0$2 16175-260-004 jet/screw o-ring 2 x 2.5 (6.5od)
02=00 0011  N/A 16012-044-681 needle set 2a 2b 2c 2d
2a=06 1111 0$5 16156-044-004 throttle w-clip
2b=07 1111 0$2 16157-044-004 needle e-clip 1.5 for 2.0 needle
2c=00 0011  N/A 16151-044-683 jet needle
2d=00 0011  N/A 16133-044-683 needle jet 2.6 x 2.0
03=00 1111  N/A 16014-044-004 top set 3a 3b 1p
3a=03 1111  N/A 16119-044-004 carb top M16-1.0
3b=02 1111 0$3 16118-044-004 cable adjuster male M6-0.75
04=00 0011  N/A 16015-044-014 chamber/valve set 4a 1n
4a=00 0011  N/A 16112-044-014 chamber cover w/valve
05=00 1111  N/A 16016-044-014 screw set 5a 5b 5c 5d 1i 1i
5a=18 1111  N/A 16163-044-014 idle speed screw
5b=19 1111  N/A 16162-259-004 idle air screw
5c=21 1111  N/A 16182-011-004 idle speed spring
5d=22 1111  N/A 16181-202-004 idle air spring
06=00 0011  N/A 16022-044-680 valve (slide) set 6a 6b
6a=09 1111  N/A 16141-044-683 throttle valve (slide)
6b=05 1111  N/A 16185-044-004 throttle spring
10=00 0022  .80 00-93500-03008 phillips screw M3 x 8
13=00 0o10N/A 99114-044-0681 main jet 68
13=00 00o N/A 00-99120-06214 main jet 62
14=00 0011  N/A 99203-044-5201 slow jet

Part Sets: Before 1968 most Honda parts were sold individually. That is how the top carb is listed and illustrated. Starting in 1968, many Honda parts were only sold in sets. That is how the bottom carb is listed and illustrated. 

Parts for the top carb that are the same as the bottom, are only listed in the bottom carb parts.

 


2. Keihin
size carb model code eng  years    frame number range      Honda models
0∅9  C4A on #063 ohc 1969-70 PC50-1000000 to 1057917   PC50 xxxxxx40 km/h
∅10  C5A on #063 ohc 1969-70 PC50-1057918 to 1060412   PC50 (1306302) 50 km
∅10  C5A on #063 ohc 1969-70 PC50-1060413 to 0000000   PC50 Little Honda (US)  
∅10  C5A on #064 ohc 1969-70 PS50-1000000 to 1001412   PS50 xxxxxx50 km/h
∅10  S5A on #064 ohc 1969-70 PS50-1001413  to 0000000   PS50 xxxxxx50 km/h
0∅9  C4B on #081 ohv 1970-71 PC50-2000000 to 2039616   PC50K1 xxxx40 km/h
∅10  C5B on #081 ohv 1970-71 PC50-2039617 to 0000000   PC50K1 xxxx50 km/h
∅10  S5B on #082 ohv 1970-71 PS50-2000000  to 0000000   PS50K1 xxxx50 km/h
0∅9  F4A on #081 ohv 1971-73 PC50-0000000 to 0000000   PC50K1 xxxx40 km/h
∅9 o F4A on #099 ohv 1970-73 PF50-1000000 to 0000000   PF50 Amigo  40 km/h
∅10  F5A on #081 ohv 1971-73 PC50-0000000 to 0000000   PC50K1 xxxx50 km/h
∅10  F5A on #099 ohv 1970-73 PF50-1000000 to 0000000   PF50 Amigo  50 km/h

1968 PC50A (Euro)
with OHC engine

1969-70 Honda PC50 (USA) with OHC engine

1973 Honda PC50K1
with OHV engine

 

 

 

 

 

 

 

 

1969-70 PC50: Before April 1970, the PC50 had a OHC engine (over head cam). Bore 42.0 mm, stroke 35.6 mm, displacement 49.3 cc. The valves were operated by a cam in the head, driven by a cam chain.

Spigot mount: The Keihin C4A, C5A, C4B, C5B carburetors for the early 1969-70 PC50A were spigot mount type. They had a round float bowl gasket (with three flat sides when installed), a push-in jet, jet pad, completely round “donut” float, all metal float needle with replaceable float seat.

1970-73 PC50K1: After April 1970, the PC50K1 had a OHV engine (over head valve). The valves were operated by pushrods from a cam down in the case.

Flange mount: The Keihin F4A, F5A, carburetors for the 1970-73 PC50K1 were flange mount type with 32mm bolt spacing. There was a diamond shaped gasket rather than an o-ring like all later flange mount carbs. Everything else was the same, round float bowl gasket (with three flat sides when installed), a push-in jet, jet pad, completely round “donut” float, all metal float needle with replaceable float seat.

Keihin C5A carburetor

Keihin F4A carburetor

 

 

 

 

 

 

 

 

#5c #5d drain plugs

 

Keyster 0605 kit for PC50A has no #1e
for C4A except no 1e, C5A  except   15 1e
for C4B except 2f 1e, C5B except 2f 15 1e
for F4A except 2g 1e, F5A except 2f 15 1e

 

 

 

#1 16010-063-000
1d 1e 1n 1p     1r

#1 16010-063-004
1d 1e 1n 1p 1q   .

#1 16010-114-305
1d 1e 1n 1p 1q 1r

 

 

 

 

 

 

 

 

1969 Honda PC50 carburetor illustration

Keihin C4A, C4B, C5A, C5B

0o quantity
o#
⇓⇓⇓⇓⇓⇓ 
Keihin (a)C4A (b)C5A (c)C4B (d)C5B (e)F4A (f)F5A
o# abcdef  price   Honda part#    description       specs
00 100000  N/A 16100-063-690 carb. C4A   ∅9  69-70 PC50
00 010000  N/A 16100-063-004 carb. C5A ∅10  69-70 PC50, PS50
00 001000  N/A 16100-081-690 carb. C4B   ∅9  70 PC50K1 < 2039617
00 000100  N/A 16100-081-014 carb. C5B ∅10  70 PC50K1 > 2039616
00 000010N/A 16100-099-690 carb. F4A   ∅9  70-73 PC50K1, PF50
00 000001  N/A 16100-099-600 carb. F5A ∅10  70-73 PC50K1, PF50
01 111011 $17 16010-063-004 gasket solo-set   1d 1e 1n 1p 1q
01 000100 $17 16010-063-000 gasket solo-set   1d 1e 1n 1p oo 1r
01 111111 $18 16010-114-305 gasket multi-set 1d 1e 1n 1p 1q 1r
1d 111111 0$2 16176-551-004 main jet o-ring 1 x 3 (5 od)
1e 111111 $10 16197-063-004 jet pad disk Ø7.3 x 1.9
1n 111111 0$7 16173-063-004 float bowl o-ring 1.5 x 40 (43 od)
1p 111111 0$5 16171-044-004 top rubber washer 10 x 15 x 1
1q 111011 0$3 16189-056-004 drain screw seal washer 6 x 8 x 0.5
1r  000100 0$5 16175-001-004 drain screw o-ring C5B 2 x 4 (8od)
02 00110N/A 16012-064-004 needle set F5A 2a 2c 2d 2f
2a 11110N/A 16051-063-004 jet needle C4A C5A C4B C5B F5A
2b 000010  N/A 16051-063-690 jet needle F4A
2c 111111 0$5 16156-044-004 needle w-clip
2d 111111 0$2 16157-044-004 needle e-clip 1.5 for 2.0 needle
2e 110000  N/A 16133-063-004 needle jet C4A C5A 2.1 x 2.5
2f  00110N/A 16133-081-004 needle jet C4B C5B F5A
2g 000010  N/A 16133-081-690 needle jet F4A
03 111111  N/A 16013-064-004 float set 3a 3b 3c 3d 3e 10
3a 111111  $13 16123-063-004 float needle (all metal)
3b 111111  N/A 16122-063-004 float
3c 111111  N/A 16127-063-014 float arm
3d 111111  N/A 16126-063-014 float hinge pin
3e 111111  N/A 16196-063-014 float pin plate
04 111111  N/A 16014-064-004 top set 4a 4b 1p
4a 111111  N/A 16119-063-004 top with pipe
4b 111111  N/A 16118-045-004 cable adjuster female M6-0.75
05 111011  N/A 16015-064-004 chamber set 5a 5c 1n 1q
05 000100  N/A 00000-000-000 chamber set 5b 5d 1n 1r
5a 111011  N/A (not sold separately) chamber bare
5b 000100  N/A (not sold separately) chamber bare
5c 111011  N/A 16164-225-004 drain screw C4A C5A C4B F4A F5A
5d 000100  N/A 16162-304-004 drain screw C5B
06 111111  N/A 16016-063-004 adjustment screw set
6a 111111  N/A 16163-063-014 idle speed screw
6b 111111  N/A 16162-044-004 idle air screw & spring
6c 111111  N/A 16181-250-004 idle speed spring
07 111111  N/A 16022-063-004 throttle valve set
7a 111111  N/A 16141-063-004 throttle valve (slide)
7b 111111  N/A 16185-044-004 throttle spring
09 111111  N/A 16194-063-004 cable pipe cover
10 222222 $1.00 93500-0300500A phillips screw M3 x 5
11 222222 $1.00 93500-040120A phillips screw M4 x 12
12 111111 $0.50 94111-030000 spring washer M3
13 222222 $0.20 94111-04000 spring washer M4
15 101010  N/A 99201-063-0550 main jet #55 push-in see jets below
15 01010N/A 99201-063-0620 main jet #62 push-in see jets below
18 111111  N/A (not sold separately) idle jet press-in tube 0.35=0.0138″

 

 


Keihin Carburetor Parts family 6,7

April 3, 2021

== carb ID# ============  M O P E D S  ===========
6.
PA 08B-A  1977-78 Honda NC50 Express xxx    30 mph TS
6. PA 08B-B  1977-79 Honda NC50, NA50  xxxx    30 mph TS
6. PA 08C-A  1978-79 Honda NC50, NA50  xxxx   
30 mph TS
6. PA 08E-A  1980-80 Honda NC50 Express xxx    30 mph TS
6. PA 08E-B  1980-80 Honda NC50 Express xxx    30 mph TS
6. PA 08D-A  1980-80 Honda NA50 Express II x   30 mph TS
7. PA 15A-A  1981-81 Honda NC50 Express xxx    30 mph TS
7. PA 16A-A  1981-81 Honda NA50 Express II  x   30 mph TS
7. PA 13B-A  1981-82 Honda NX50 Express SR x   30 mph TS
7. PA 13B-B  1982-83 Honda NC50 Express xxx     30 mph TS

7. PA 13E-A  1982-83
Honda NU50 Urban Express 30 mph TS
7. PA 25A-A  1982-83 Honda NC50AA, NU50AA    25 mph TS

 

 

 

 

 


6. Keihin
size     carb  model code  year 00 frame number range  000  model
∅12 PA08B-A or B #147 1977 NC50-1139281 to 0000000 NC50 Express (US)    30 mph
∅12 PA08B-A or B #147 1978 NC50-2000013 to 0000000 NC50 Express (US)    30 mph
∅12 PA08E-A or B #147 1979 NC50-2100011 to 0000000 NC50 Express (US)    30 mph

∅12 PA08E-A or B #147 1980 NC50-2200005 to 0000000 NC50 Express (US)    30 mph
∅12 PA08B-B    on #163 1979 AB01-5000001 to 0000000 NA50 Express II (US) 30 mph

∅12 PA08D-A    on #163 1980 AB01-5200001 to 0000000 NA50 Express II (US) 30 mph

 

1977 Honda NC50 Express

1978 Honda NC50 Express

’79 NC50 Express

 

 

 

 

 

 

 

 

 

1980 Honda NC50 Express

1980 Honda NA50 Express II

 

 

 

 

 

 

 

 

 

 

 

#0  16100-147-675
Keihin PA08B-A

#0 16100-147-676
Keihin PA08B-B

#0 16100-147-711
Keihin PA08E-A

 

 

 

 

 

 

 

 

 

#0 16100-147-712
Keihin PA08E-B

16100-163-771
Keihin PA08D-A

 

 

 

 

 

 

 

 

Flange Mount: 38 mm hole spacing. 2 x 20 (24 od) intake o-ring.

Honda Express carburetor versions, showing things that are different.

Honda Express carburetor versions

Cable choke: This carburetor has a throttle cable and a choke cable coming straight up and looping around. It has no vent hoses, vacuum hoses, or oil lines going into it. The oil injection goes into the intake manifold. The float reservoir vent is just a small tube slanting downward.

As with most Honda carburetors, fuel is never allowed to spill onto the engine or anything else. Instead an overflow tube inside the float chamber allows any overflow fuel to flow out and down the drain hose and onto the ground below the engine.  

The 1977-79 Honda NC50 and NA50 each had two carburetor versions, PA08B-A and PA08B-B. Regardless of the year, or the VIN number, they could have either version. So the customer had to look at the model number stamped into the carburetor, and tell the Honda dealer that number, to get certain parts correct. 

Oil injection hose location: The 1977-79 Honda Express had the oil hose going into the intake manifold, not the carburetor. The 1980 and later models had the oil injection hose going into the carburetor at the throttle slide area. There must have been some benefit, like maybe throttle slide lubrication.

16010-143-620
has a, c, d, e, f, g
for PA08 BA

16010-143-305
a, c, d, e, f, g, h, i 
for PA08 BA

16010-147-004
has b, c, f, g
for PA08 BB, EB

16010-147-711
has b, c, d, f, g
08 BB EB DA EA

16010-147-505
has b, c, d, f, g, i
08 BB EB DA EA

 

 

 

 

 

 

 

 

 

    quantity
o#
⇓⇓⇓⇓⇓ 
Keihin PA(a)08BA (b)08BB (c)08EA (d)08EB (e)08DA 
o# abcde price  Honda part#x  description xxx specs
10 1ooooN/A 16100-147-673 

10 1ooooN/A 16100-147-675 carburetor 77-78 NC50 PA 08B-A
10 o1oooN/A 16100-147-676 carb 78-79 NC50 NA50 PA 08B-B
10 oo1o0N/A 16100-147-711 carburetor 
1980 NC50 PA 08E-A
10 oo01o  N/A 16100-147-712 carburetor 
1980 NC50 PA 08E-B
10 oooo1N/A 16100-163-771 carburetor  1980 NA50 PA 08D-A

o1 10ooo $21 16010-143-620 gasket solo-set   1a o c d e f g
o1 10ooo $23 16010-143-305 gasket multi-set  1a o c d e f g h i

o
1 01o1o $23 16010-147-004 gasket solo-set   oo b c o o f g
o1 o1111 $23 16010-147-711 gasket solo-set   oo b c d o f g
o1 o1111 $21 16010-147-505 gasket multi-set oo b c d o f g o i

1a 100o0 $$3 00000-000-000 top rubber washer 10 x 18 x 1
1b o1111 $$8 00000-000-000 top rubber washer 13 x 16.5 x 1
1c 11111 $$2 00000-000-000 intake o-ring 2 x 20 (24 od) 
1d 1o1o1 0$2 16176-551-004 jet or screw o-ring 1 x 3 (5 od)
1e 1o0oo $10 16197-063-004 jet support pad disk Ø7.5 x 1.8
1f 11111 $15 00000-000-000 float bowl gasket  Ø1.5 NC50-type
1g 11111 $$2 00000-000-000 drain plug o-ring 1.5 x 4 (7 od)
o2 1oo1o $21 16011-881-741 float needle valve  stirrup
o2 o11o1 $24 16155-883-005 float needle valve regular
o3 1o1o0  N/A 16012-147-004 needle set 3a 3b 3c 3d 08BA EA
o3 ooooo $22 16012-130-640 needle set 3a 3b 3c 3d PA 03A-A
o3 ooooo $22 16012-165-014 needle set 3a 3b 3c 3d PA 03B-A

o3 o1o11 $15 16012-147-014 needle set 3a 3b 3c 08BB EB DA
3a 11111 0$5 16156-044-004 jet needle w-clip
3b 11111 0$2 16157-044-004 jet needle e-clip 1.5 for Ø2.0 needle
3c 11111 $10 00000-000-000 jet needle Ø2.0 D348 thick 08B-A,
3c 11111 $10 00000-000-000 PA 08B-B, 03A-A, 00A, 01A

3c ooooo $10 00000-000-000 jet needle Ø2.0 D117 thin 03B-A,
3c ooooo $10 00000-000-000 PA 03C-A, 03D-A, 03H-B, 03M-A, etc
3d 1o1oo  N/A 00000-000-000 needle jet (emulsion tube) 08BA 08EA
3d o1o11  N/A 00000-000-000 needle jet & jet fixed 08BB 08EB 08DA

3d ooooo $10 00000-000-000 needle jet (emulsion tube) PA 03A-A
3d ooooo $10 00000-000-000 needle jet (emulsion tube) PA 03B-A
o
4 1oo1o  N/A 16013-143-620
o4 1oo1o $38 16013-099-691 float set 4a oo 4c 4d black stirrup
o4 o11o1 $28 16013-147-004 float set oo 4b 4c 4d white regular
4a 1oo1o  N/A 00000-000-000 float bare, solid black foam stirrup
4b o11o1 $21 00000-000-000 float bare hollow white plastic regular
4c 11111 $$4 00000-000-000 hinge pin substitute Ø2 x 18.5
4d 11111 $$3 0-93600-04006 hinge screw M4x6 sunk phillips

1977-79 NC50 idle adjustment screws
7a idle speed screw, tighter is faster
7c idle air mix screw, tighter is richer

o5 1oooo $23 16014-143-620 top set substitute 5a 1a M20-1.0
o5 o1111 $22 16014-147-004 top set substitute 5a 1b M18-1.0
o6 1ooooN/A 16015-147-004 chamber set A 6a oo 6c 1e 1f 1g for jet pad
o6 o1111  N/A 16015-147-014 chamber set B oo 6b 6c oo 1f 1g for no pad
6a 1oo0oN/A 16015-147-004 float bowl A shallow with pad holder
6b o1111  N/A 16015-147-014 float bowl B shallow, no jet pad holder
6c 11111 $16 00000-000-000 
float drain screw M6x20 special
o7 11o1o $15 16016-143-620 screw set 7a b c d idle air
o
7 oo101  N/A 16016-147-711 screw set 7a b o d e f g idle fuel

7a 11111 $$4 00000-000-000 idle speed screw M4x19 special
7b 11111 $$2 00000-000-000 idle speed screw spring Ø5.6 x 10
7c 11o1o $$6 00000-000-000 idle air screw M6-0.75 thick tip
7d 11111 $$7 00000-000-000 idle air or fuel spring Ø4.8 x 9
7e oo1o1  N/A 00000-000-000 idle fuel screw M6-0.75 thin tip
7f  oo1o1 $$3 00000-000-000 idle fuel screw washer 3.1 x 5.0 x 0.5
7g oo1o1 0$2 16176-551-004 idle fuel screw o-ring 1 x 3 (5 od)

1980-83 NC50 idle adjustment screws
7a idle speed screw, tighter is faster 
7e idle fuel mix screw, tighter is leaner

o8 11111 $38 16022-143-620 valve set 8a, 8b
8a 11111 $22 00000-000-000 throttle slide Ø13 #15A
8b 11111 $12 00000-000-000 throttle spring original Ø9.5 x 42
8b
11111 $$7 00000-000-000 throttle spring substitute shorter, stiffer
o9 11111 $25 16046-147-004 choke set substitute 9a 9b 9c
9a 11111 $10 00000-000-000 choke top substitute plastic M12-1.0
9a 11111 $15 00000-000-000 choke top substitute metal M12-1.0
9b 11111 $$4 00000-000-000 choke spring substitute
9c 11111 $12 00000-000-000 choke slide substitute
11 11111 $2.00 16118-166-004 rubber boot substitute Dellorto
12 22222 $1.00   93500-04012 bowl screw M4x12 pan phillips
13 22222 $0.20   94111-04000 lock washer M4 split
14 11111 $1.00 95001 – 35003 hose substitute 1/8 x ¼ 3.1 x 6.3

1977-80 NC50 cable choke top substitute

15 11111  N/A 95002 – 02070 drain hose clamp B7 (for 7 not 6.3)
16 10o0o  
N/A 99201.081.0780 push-in jet 78 08BA

16 10o0o $23 substitute jet, #70 drilled to 78 08BA
16 01111 N/A fixed needle jet & jet pressed in 08BB EA EB DA
this jet is 0.78mm 0.0307″, cleaned with a #69 drill 0.0292″     

 

Main Jet: On PA08BB, EA, EB and DA versions the main jet is a tamper-proof tight press-fit type, in the center. The jet cannot be removed, and cannot be replaced. It is 0.78 mm – 0.0307″, and can be cleaned perfectly with a #69 drill 0.0292″.    

On a PA08BA the main jet presses or slides in and out, and is supported by a rubber disk. If the disk is missing, the jet can slide downward, allowing fuel to get past the jet o-ring, causing a rich fuel mixture.

Idle Hole Cleaning: Near the engine side of the carb body is a brass tube that dips down into the liquid gasoline. That tube, about 1.5 mm (0.060″) inner diameter and 20mm long, leads to the idle or pilot jet, which is about 0.30 mm (0.012″). The idle jet gets clogged from sitting, then the engine will run but won’t idle. Nothing but a very thin (0.010″) steel guitar string will clean it out. See below about jet drills and cleaning tiny jets. Ultrasonic parts cleaners, carb spray, carb dip, and compressed air are not usually effective. Another way to clean out the idle jet is to 1) place a drill bit that fills the hole (so it does not get crushed), 2) clamp it with a small vise grips, 3) rotate back and forth while pulling, 4) when it comes out, the actual hole is easy to see and clean, 5) press it back in the same way it came out.

Strong solvent is needed to dissolve varnish or tar residue left from years of sitting. Carburetor spray, parts dip, or acetone all help clean out the tar, sometimes with a lot of scraping, brushing or rubbing. Always remember to remove all rubber things first, to not let the rubber touch the solvent. Strong solvents will swell soft rubber, deforming it. Never soak the whole carburetor in strong solvent. In this way, Shaun (at Royal Cyclery and later at Myrons Mopeds) has successfully cleaned out over 100 Honda Express carburetors, without ever replacing any of the rubber gaskets. Part of the reason was they were only sold at Honda dealers, but nonetheless, they are not needed in a normal service or clean-out.

Keihin PA08C-A: This is approximately for a 1979-80 NC50, or maybe NA50. It is identical to a PA08B-B. It has the same white float, non-stirrup float needle, fixed jet, 18mm top threads, and same gaskets. The idle mixture screw type is unknown. No photo available. 

 


7. Keihin
size  carb  model code  years       models
∅12 PA15A-A on #190 1981-81 Honda NC50 Express (US) xxxxx xxxx 30 mph
∅12 PA16A-A on #193 1981-81 Honda NA50 Express II (US) xxxx xxx  30 mph

∅12 PA13B-A on #187 1981-82 Honda NX50 Express SR (US) xxxx xx  30 mph
∅12 PA13B-B on #GA6 1982-83 Honda NC50 Express (US) xxxxx xoxx 30 mph

∅12 PA13E-A on #GC1 1982-83 Honda NU50 Urban Express (US) xxxx 30 mph

∅12 PA13E-A on #GC1 1982-83 Honda NU50M Urb. Expr. Deluxe (US)  30 mph
∅11 PA25A-A on #GA6 1982-83 Honda NC50AA Express (Iowa) xxxxxx25 mph
∅11 PA?????   on #GC1 1982-83 Honda NU50AA Urban Express (Iowa)   25 mph
∅10? PA25A-A on#GC1 1982-83 Honda NU50MA Urb. Ex. Deluxe (Iowa) 25 mph

 

1981 NC50 Express

1981 NA50 Express II

1981 NX50 Express SR

1982 NU50 Urban Express

 

 

 

 

 

 

 

#0  16100-190-672
Keihin PA15A-A

#0  16100-193-672
Keihin PA16A-A

#0  16100-187-673
Keihin PA13B-A

 

 

 

 

 

 

 

 

#0 16100-GA6-671
Keihin PA13B-B

#0 16100-???-???
Keihin PA25A-A

#0  16100-GC1-671
Keihin PA13E-A

 

 

 

 

 

 

 

 

Flange Mount: 38 mm hole spacing, 2 x 20 (24 od) o-ring on NC50, NA50 (PA15A-A, PA16A-A, PA13B-B)
Flange Mount: 32 mm stud spacing, 2 x 18 (22 od) o-ring on NX50, NU50, NU50M (PA13B-A, PA13E-A)
Flange Mount: 36 mm hole spacing, 2 x 20 (24 od) o-ring on NC50I, (PA25A-A)

Vacuum-operated automatic choke: These carburetors feature a screw-in main jet, and a built-in vacuum-operated (not electric) automatic choke. When the temperature switch on the head is cold, it allows the engine vacuum to raise the choke plunger up, which opens a new fuel passage, to enrich the mixture during cold starting. As the engine warms up, it closes the vacuum, allowing the thin spring to pull it back down, for normal running. The more precise term for this is “automatic vacuum operated cold start fuel mixture enrichment device”. The 1981-83 automatic choke device itself is not replaceable.

The vacuum source hose has a check ball valve that only allows air flow into the carburetor venturi, and not back out. It needs this even though there is reed valve, because there is still some residual reverse flow caused by the forward and reverse motion of the piston.

The vacuum choke that came out in 1981 did not last long. After 1983, 50cc on-road Honda’s had electric chokes, because they were electric-start scooters with 12 volt batteries. 

Identical twins: The PA16A-A looks identical to the PA15A-A. It is on the 1981 Honda NA50 Express II, the final year of that USA-only model. They both have 38 mm flange hole spacing, #75 screw-in jet, 20 mm intake o-ring and the non-stirrup type B float needle. The only difference is the top cable curved pipe. On a PA15A-A it is permanently attached to the screw-on top cap with a swivel joint, while on a PA16A-A the curved cable pipe is detachable.

Intake studs: After 1981 these carbs had studs instead of threaded holes in the mounting flange, except for PA25A-A. PA13B-A and PA13E-A studs are spaced 32 mm with a 18mm intake o-ring. PA13B-B studs are spaced 38 mm, with a intake o-ring 20 mm. 

Iowa carb: The PA25A-A is like a PA13B-A, with M18-1.0 top cap threads, vacuum-operated automatic choke, choke jet in float bowl, tall 2.5 x 1.5 float bowl gasket, non-stirrup type float and float needle, screw-in main jet size 75. The only noticeable difference is the absence of studs.

Iowa cylinder: The exhaust port is restricted. Here left is 49-state, right is Iowa.

#1 16010-190-004
for 15A 16A 13BB 25A

#1 16010-187-003
for PA 13BA 13EA

#1  16010-GF8-305 for
for PA 13BA 13EA

 

 

 

 

 

 

 

 

 

PA 15AA 16AA 13BA 13BB 13EA

      quantity
o#
⇓⇓⇓⇓⇓⇓ 
PA (a)15AA (b)16AA (c)13BA (d)13BB (e)25AA (f)13EA
o# abcdef price  Honda part#x  description xxx specs
00 1o0000  N/A 16100-190-672 carburetor ’81-81 NC50 PA15A-A
00 o10000  N/A 16100-193-672 carburetor ’81-81 NA50 PA16A-A
00 o01000  N/A 16100-187-673
carburetor ’81-82 NX50 PA13B-A
00 o00100  N/A 16100-GA6-671 carburetor ’82-83 NC50 PA13B-B
00 o0001N/A 16100-
GA6-671 carburetor ’82-83 NC50AA PA25A-A
00 o0000
N/A 16100-GC1-671
carburetor ’82-83 NU50 PA13E-A
01 001
001 $24 16010-187-003 gasket solo-set   1b o d g h k
01 110110 $24 16010-190-004 gasket solo-set   1b c d g o k
01 001001 $25 16010-GF8-305 gasket multi-set 1b o d g h k t u

1b 111111 $$8 00000-000-000 top rubber washer 13 x 16.5 x 1
1c 110110 $$2 00000-000-000 intake o-ring 2 x 20 (24 od) 
1d 111111 0$2 16176-551-004 idle fuel screw o-ring 1 x 3 (5 od)
1g 111111 $$2 00000-000-000 drain plug o-ring 1.5 x 4 (7 od)

1h 001001 $$2 00000-000-000 intake o-ring 2 x 18 (22 od)
1k 111111 $22 00000-000-000 float bowl gasket 2.5 tall by 1.5 wide
02 0010?0  N/A 16012-187-671 needle set 2a 2b

02 1100?0  N/A 16012-193-671 needle set 2a 2b 2c 2d
02 0001?1  N/A 16012-GA6-671 needle set 2a 2b 2c oo 2e

02 0000?1  N/A 16012-GC1-671 needle set 2a 2b 2c oo 2f

2a 111111 0$5 16156-044-004 jet needle w-clip
2b 111111 0$2 16157-044-004 jet needle e-clip for 1.5 clip groove
03 111111 $28 16013-147-004 float set white 3a 3b 3c
3a 111111 $21 00000-000-000 float bare white plastic regular
3b 111111 $$4 00000-000-000 hinge pin substitute Ø2 x 18.5
3c 111111 $$3 0-93600-04006 hinge screw M4x6 sunk phillips
04 1o0000  N/A 16014-190-014 top set NC50 fixed cable pipe M18-1.0
04 o10000 $24 16014-147-014 top set NA50 detachable pipe M18-1.0
04 o01110  N/A 16014-187-013 top set NX50, 82-83 NC50 M18-1.0

04 o00001  N/A 16014-GB2-003
04 o00001  N/A 16014-GB0-831 

04 o00001  N/A 16014-098-980 top set NU50 fixed cable pipe M18-1.0

05 110000  N/A 16015-191-034 chamber set deep bowl with choke jet
05 001000  N/A 16015-187-671 chamber set deep bowl with choke jet
05 0001?0  N/A 16015-GA6-671 chamber set deep bowl with choke jet

05 0000
?N/A 16015-187-043 chamber set deep bowl with choke jet
06 000111 $32 16016-191-004 idle fuel screw set
06 111000 $32 16016-187-003 idle fuel screw set

6e 111000  N/A 00000-000-000 idle fuel mixture screw M6-0.75 special
6b 111111 $$7 00000-000-000 idle fuel mix screw spring Ø5 x 9
6f  111111 $$3 00000-000-000 idle fuel mix screw washer 3.1×5.0x0.5
07 111111 $0016028-187-003
07 111111 $15 16028-GC8-004 idle speed screw and spring 7a 7b

7a 111111 $$4 00000-000-000 idle speed screw M4x19 special
7b 111111 $$2 00000-000-000 idle speed screw spring Ø5.5×10
08 1100?0 $38 16022-143-620 throttle slide & spring
08 0010?1  N/A 16022-187-731 throttle slide & spring
08 0001?1 
N/A 16022-191-004 throttle slide & spring
8a 110000 $22 00000-000-000 throttle slide Ø13 #15A
8b 110000 $12 00000-000-000 throttle slide spring Ø9.5 x 42

NC50 idle fuel screw
top: original 
bottom: replacement

10 100000  N/A 16118-086-004
10 100000  N/A 16118-166-004 cable rubber boot
10 101110  N/A 16118-187-003 cable rubber boot
10 00000N/A 16118-GB4-003 cable rubber boot

11 111111 $24 16155-883-005 float needle valve KL 18-4608
12 110110  N/A 16199-435-771 overflow hose 3.0 x 6.5
12 00100N/A 16199-187-003 
12 00100N/A 16198-HC0-405 overflow hose 3.0 x 6.5
13 001000  N/A 16608-187-000 control hose with check ball 5 x 10

13 110000  N/A 16608-193-670 control hose with check ball 5 x 10
13 000110  N/A 16608-GA6-670 control hose with check ball 5 x 8

13 00000N/A 16608-GC1-000 control hose with check ball 5 x 8

14 222222 0$1 93892-04012-08 screw & washer M4x12 pan phillips
15 111111  N/A 95002 – 02070   hose clamp B7 vacuum source hose
16 111000  N/A 95002 – 02100   hose clamp B10 for control hose
16 000111  N/A 95002 – 02080   hose clamp B8 for control hose

17 111111  N/A 95002 – 02650   hose clamp B6.5 for overflow hose
18 111111  N/A
 95005 – 35001   vacuum (source) hose 3.5 x 7 x 130
19 oo0010 $$7 99101-187-0700 screw-in jet #70 M6-0.75 PAMOA PA25A ? 78-80 Indian, 82-83 NC50I
19 110100 0$7 99101-187-0750 screw-in jet #75 M6-0.75 PA15A 16A 13BB 81-83 NC50, 81 NA50
19 oo1000 0$7 99101-187-0780 screw-in jet #78 M6-0.75 PA13BA 81-82 NX50
19 oo0001 0$7 
99101-187-0850 screw-in jet #85 M6-0.75 PA13EA 82-83 NU50

 

 

Float Valve Seat: On these carburetors the float seat (the cup that the float needle valve slides in) is carved into the actual carburetor body, and is not replaceable. Polish it with a spinning Q-tip and polish, such as Turtle Wax. 

Choke jet: On all of these NC50-type carbs, both shallow and deep-float-bowl versions, there is a choke jet, pressed into a corner of the float bowl. When it gets clogged the engine will only start easily when it is warm.

Verify all jets and fuel or air passageways are open, using wires and or visually with carb spray (wear goggles).

Cable Differences: You can tell what year range a Honda Express is from a distance. A 1977 to 1980 has two cables, a throttle and a choke cable coming straight up from the carburetor.  A 1981 has just a throttle cable coming straight up, but also a vacuum hose for the choke and a float vent hose.  A 1982 to 1983 has a black plastic curved elbow on top, that redirects the throttle cable forward and down, a vacuum hose for the choke, and a vent hose. A 1982-83 also has a different frame, a low headlight, and a two speed transmission.

The Honda Express throttle cable curves rearward and loops downward to get below the carburetor, and then goes forward into the frame tube. The loop design adds friction, but it makes a good clean step-thru frame without any cables or wires hanging out.  

1982-83 NC50 hoses

Comparison of PA MOA-A, PA 08B-B, PA 08B-A, and PA 15A-A

 

 

 

 

 

 

 

 

 

Keihin idle mixture screw channels
Left PA08B-B with idle air screw
Right PA15A-A with idle fuel screw

 

 

You can tell the difference between a carb with an idle air mixture screw, and a carb with an idle fuel mixture screw, by the shape of the casting at the top of the float chamber.

 

 

 

 

 

 

 

 


Domino “80’s-90’s Solex”

April 2, 2021

S. Domino “80’s-90’s Solex”

1999-05 Solex 3800

1986-88 Solex 3800

SB and SA controls for 1986-2005 Solex

 

 

 

 

 

 

 

This right control is special for late model Solex.  It was on 1986-88 S 3800 made in France  by Motobecane, and the re-make of that, 1999-2005 Solex 3800 made in Hungary by Impex. The throttle is self-closing, unlike most older Solex’s. What’s special is the front (right) brake also controls the throttle (gas). So it has an “either or” mechanism.

 

4. Domino late 80’s controls on 1999-05 Impex Solex 3800

0SA00  R control assembly
0S500  R housing
0S600  twist tube plastic
0D000  R grip 25 x 120
0S800  cursor to brake cable
0S900  cursor to throttle cable
10  P20R  R brake lever
11  S110  throttle cover
12  D14K  brake cable anchor pin
13  S130  cover screw
14  D800  brake pivot bolt
15  D700  pivot bolt nut M6 flange
16  D160  clamp bolt   M6 x 18 allen
17  D150  clamp tube
18  S180  L housing
19  SB00  L control assembly
21  D000  L grip 22 x 120
22  P20L  L brake lever
23  D000  decomp lever
24  D000  decomp lever retaining ring

 

 

 

 


Domino “80’s-90’s Piaggio”

April 2, 2021

P. Domino “80’s-90’s Piaggio”

 

This P controls family has (same as V)
1) threaded-bottomless brake cable holes
2) threadless-bottomed start cable hole
3) threadless-bottomed throttle cable hole

 

The right control (throttle and front brake) is a sliding block type, where the twist tube (barrel) has a spiral slot that moves a sliding block back and forth. The sliding block also contains a pinch bolt to attach the cable wire. So the throttle inner cable is a single-ended type that can slide out and be replaced separately. 

189022 PBg and 189824 PAsg 
with brake switch holes, PBg has thumb lever
P20L, P20R and P19 black plastic levers
189021 P18g and 189825 P5sg gray housings
PAsg has square Grabor switch mount with
D1 slider, D2 screw, D6a steel w/flange 100
for 1979-85 Piaggio Si (SIV-US)

188056 PB and 188057 PA 
no brake switch holes, PB has thumb lever
P20L, P20R and P19 black plastic levers
188058 P18 and 188059 P5 black housings
PA has D1 slider D2 screw D6 steel tube 100
for 1984-85 Piaggio Bravo (most), Si (most)

 

 

 

 

 

 

 

 

 

 

housing P5sg

control PAsg

 

 

 

 

 

3a. Domino-Piaggio early 1980’s (early 70s illustration)

 # mm# qty Piaggio#  price  description     -B is Belgium, -S is Sweden, -N is Norway, /B is with blinkers
0
D21c 1 185256 n.a.-00 right grip ∅25 x 100 early octagon
0
D600 1 123393 $15-00 twist tube steel,  plain type  ∅25 x 100
02  D6a0 1 174993 00-$12 twist tube steel spring type ∅25 x 100 SIV-US ’79-85
0D400 1 123390 000-$5 grip washer
0
D100 1 123392 $18-00 sliding block
0D200 1 123391 $5-000 pinch screw
0D11K 3 177072 $5-000 lever spring
0P20R 1 177340 $16-00 right brake lever black plastic
0D300 1 123389 $6-000 twist tube (throttle barrel) screw
0D230 1 174994 $5-000 throttle assist spring SIV-US ’79-85
10  P500 1 188059 n.a.-00 right housing black no stop switch hole, no switch mount
10  P5sg  1 189825 $28-00 right housing gray w/stop switch hole, sq. switch mount SIV-US
10  P5sg  1 189825 n.a.-00 right housing gray w/stop switch hole, sq. switch mount Bravo-B, SIV-B, SIM-S
10  P5a0 1 212518 n.a.-00 right housing black no stop switch hole, lower kill button mount SIV/B
11  D160 1 123394 $1-000 right clamp bolt M6 x 18 allen and tube D15
12  V290 2 103964 $4.00   cable adjuster A3a M6-1.0 round w/nut for Vespa brake cables
12  V29s  2 101010 $2.00   cable adjuster A2  M6-1.0 hex with hex nut substitute
13  D14K 2 177073 $3-000 brake/start cable anchor pin has a step ∅8-∅9
14  D800 2 121780 $3-000 brake pivot bolt  M6 x 25 slot head and nut D7
15  D130 1 121781 $3-000 start pivot bolt  M6 x 23 slot head and nut D7
19  P20L 1 176945 $16-00 left brake lever black plastic
21  D22c 1 185257 n.a.-00 left grip ∅22 x 100 early octagon
22  P180 1 188058 n.a.-00 left housing black no stop switch hole, no switch mount
22  P18g 1 189021 $13-00 left housing gray w/stop switch hole, horn button mount SIV-US ’79-85
22  P18h 1 189043 n.a.-00 left housing gray w/stop switch hole, switch mount Bravo-B, SIV-B, SIM-S
22  P18a 1 212520 n.a.-00 left housing black no stop switch hole, switch mount SIV/B, EVL-N
23  D170 1 123395 $3-000 left clamp bolt M6 x 20 allen and tube D15
24  P190 1 176946 $16-00 start (decomp) lever black plastic ∅5.5 x 8 cable end
34  15863 2 126939 $2-000 brake light switch rubber cover boot               Bravo-B, SIV-US ’79-85
35  09343 2 126938 00-$14 brake light switch normally open when installed Bravo-B, SIV-US ’79-85
0PA00 1 188057 n.a.-00 right control black no stop switch hole, no switch mount
0PAsg 1 189824 00-$45 right control gray w/stop sw. hole, kill switch mount SIV US ’79-85
0PAag 1 188562 n.a.-00 right control gray w/stop sw. hole, kill switch mount Bravo-B, SIV-B, SIM-S
0PAa0 1 212517 n.a.-00 right control black no stop sw hole, lower kill button mount SIV/B, EVL-N
0PB01 1 188056 n.a.-00 left control black, no stop switch hole, no switch mount
0PBg0 1 189022 n.a.-00 left control gray w/stop switch hole, horn button mount SIV-US ’79-85
0PBh0 1 189044 n.a.-00 left control gray w/stop switch hole, switch mount Bravo-B, SIV-B, SIM-S
0PBa0 1 212519 n.a.-00 left control black no stop switch hole, switch mount SIV/B, EVL-N

 

 

 

 

3b. Domino-Piaggio late 1980’s (same early 70s illustration)

 

 

 

 


housing P5ag

PA2g  PB1g   The right control has a helper spring.

PA2g    n.a.-00  R control plain gray 
PB1g    n.a.-00  L control plain gray 
P5ag    $27-00  R housing plain gray  
P18g    n.a.-00 
L housing plain gray  

 

 


PA1b  PB1b   The right control has no helper spring.

PA1  n.a.-00R control plain black 
PB1  n.a.-00L control plain black
P5    n.a.-00
R housing plain black
P18n.a.-00L housing plain black

 


Piaggio late 80’s

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Domino “80s black” Controls

April 2, 2021

B. Domino “1980’s black”

 

This B controls family has
1) threaded-bottomless brake cable holes
2) threaded-bottomless start cable hole
3) threaded-bottomless throttle cable hole

 

Domino “80’s black” controls were on some mopeds from about 1984 to 1991. The lever blades are black plastic. The cast aluminum housings are black, and have a large space for integrated CEV switches. 

BB7  MMI#DB8K
Domino 0904
has no lower lever
B18K housing

DA7K Domino "80s black" throttle and brake control

BA7  MMI#DA7K
has no lower lever, has
D1K slider, D2 screw
D6K plastic tube 110
B5K housing #D5K

DB7K "80s black" brake and start control

BB7s  MMI#DB7K
has lower 3-finger lever
B18Ks housing

DA7K Domino "80s black" throttle and brake control

BA6 
has no lower lever, has
D1 slider, D2 screw
D6L steel tube 110
B5L housing

 

 

 

 

 

 

 

 

 

BA9d  
has a thumb lever, has
D1K slider, D2L screw
D6Kl plastic tube 120
B5Kd housing

DA8K Domino "90s black" throttle and brake control

BA8d  MMI#DA8K
has a thumb lever, has
D1 slider, D2L screw
D6L steel tube 110
B5Ld housing #D5L

BB8d 
has a lower thumb lever
B18Kd housing

 

Here are the “80’s black” controls. The grips are not included with assemblies, but are sold separately.

 

 

 

 

 

 

BA10  motorcycle
has no lower lever, has
D1K slider, D2 screw
D6Kl plastic tube 120
B5K housing #D5K

BW7  wrap-around
has no lower lever, has
D6kw wrap-around
plastic twist tube 110
B5Kw housing

 

80’s-90’s US-models with these controls:

Garelli mopeds 1985-88 had BB7s, BA7
Tomos mopeds 1986-91 had BB7,   BA6
Trac mopeds     1985-89 had BB7s, BA8d
Derbi mopeds   1987-89 had BB8d, BA9d
Trac
 DH100      1987-90 had BB10, BA10
Jawa mopeds   1993-95 had BB7,   BA7 or 6?

 

 

 

 

2. Domino controls “80’s black” all parts

left D1, right D1K

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

left D2L. right D2

000D1  $18-00  sliding block for metal twist tube
00D1K  $12-00  sliding block for plastic twist tube
000
D2  $5-000  pinch screw regular
00D2L  $8-000  pinch screw small head
000D3  $6-000  screw that holds twist tube
0oB5K  $35-00  R housing brake/throttle for BA7     on ’84-86 Garelli
0B5Kd  $39-00  R housing brk/throttle/choke for BA9d ’86-89 Derbi
0oB5L  n.a.-00  R housing brake/throttle for BA6      on ’85-91 Tomos
0B5Ld  $39-00  R housing brk/throttle/choke for BA8d ’85-89 Trac
0oD6K  n.a.-00  throttle twist tube plastic for 110  uses D1K sliding block
0.D6Kl  $29-00  throttle twist tube plastic for 120  uses D1K sliding block
00D6L  $22-00  throttle twist tube steel    for 110  uses D1 sliding block
000D7  $2 - $1  nut for pivot bolt M6-flange
000D8  $3-000 brake and start pivot bolt
oD11K  $5-000  brake helper spring R & L
oD14K  $3-000  brake and start cable anchor, has a step ∅8-∅9 
00D15 
$4-000  cone-tube that wedges into handlebar
00D16 
$1-000  clamp bolt   M6 x 18 allen
0B18K  $32-00  L housing brake only       for BB7 on ’85-91 Tomos, ’93-95 Jawa
B18Ks   $35-00  L housing brake/clutch    for BB7s on ’85-on Garelli, ’85-89 Trac
B18Kd  n.a.-00  L housing brake/decomp for BB8d on ’86-89 Derbi
oD19K  $20-00  L 3-finger (start) lever    D19K lever parts are same as D20K
D20Kr   $14-00  R lever black plastic replica
D20Kl   $14-00  L lever black plastic replica

oD21K  $15-00  R grip ∅25 x 110 octagon style black
0D21L  $15-00  R grip ∅25 x 120 texture style  black

oD22K  $10-00  L grip ∅22 x 110 octagon style black
0D22L  $10-00  L grip ∅22 x 120 texture style  black
00D23  $5-000  throttle helper spring 3-loop

00G24  $4.00    cable adjuster for throt & choke A1b M5-0.8 w/nut round
00V29  $4.00    cable adjuster for brake F and R A3a M6-1.0 w/nut round
00D35  $8-000  R/L thumb lever ∅5.9 cable end hole
00D36  $2.00    choke/decomp cable pinch bolt ∅5.5 x 8      
00D37  n.a.-00  thumb lever retaining rivet   must drill and tap
00BB7  $45-00  L control assy, no lower lever       on ’85-91 Tomos, ’93-95 Jawa
0 BB7s 
$63-45  
L control assy with 3-finger lever on ’85-89 Trac, ’84-86 Garelli
0BB8d  n.a.-00 
L control assy with thumb lever  on ’86-89 Derbi mopeds
00BA6  n.a.-00
  R control assy, no lower lever     on ’85-91 Tomos mopeds
00BA7  n.a.-00
  R control assy, no lower lever     on ’84-86 Garelli, ’93-95 Jawa
oBA7w  $65-00 
R control assy, no lower lever, wrap-around, takes 2-ended cable

0BA8d  $75-00 
R control assy with thumb lever  on ’85-89 Trac mopeds
0BA9d  n.a.-00 
R control assy with thumb lever  on ’86-89 Derbi mopeds
0BA10  $78-00 
R control assy, no thumb lever    on ’87-90 Trac DH100

 

 


Domino Menu

April 2, 2021

updated 2021-04

Select:

D. 1970’s – 1980’s Domino shared parts
D. Domino 1970’s
housings and controls
V. Domino-Vespa
housings and controls
G. Domino-Garelli
housings and controls
E. Domino 1980’s
housings and controls

B. 1980’s-90’s Domino “Black”

P. 1980’s-90’s Domino-Piaggio

S. 1980’s-90’s Domino-Solex

 

 

 

Domino

Domino controls (comandi) are made in Italy since the 1950’s. Domino controls are found on most Italian mopeds, such as Arciero, Aspes, Baretta/Piccoli, Beta, Bianchi, Cimatti, Concord/Fantic, Demm, Gadabout, Garelli, Malaguti, Motobecane Sebring, Motomarina, Motron, Negrini, Pacer/Italtelai, Snark, late 80’s Tomos, and Vespa/Piaggio. Other Italian mopeds had PV, OSL, or Ci.Ti controls. Domino has made, and still does make, many other high quality motorcycle controls.  

1982 MMI parts list
for 1970-77 controls

MMI Part Numbers: In 1982 the biggest USA moped part importer/distributor Marina Mobili Inc assigned Domino part numbers that began with “D”. The “D” parts were for sale to the public through all moped dealers.

MM Part Numbers: Domino also made controls specifically for Vespa and Garelli. Those parts were only sold through Vespa or Garelli dealers. They never did have a MMI part number. Myrons Mopeds made up the “V” and “G” part numbers to agree with the corresponding “D” part numbers used by MMI. 

Families: The control parts are organized into families, based on the way the cables attach.

Brake light switch holes: Many non-US models do not have brake lights. So their Domino housings don’t have threaded holes for brake light switches. Their Domino “70’s chrome” levers do not come with the inner push plate that pushes the button on the brake light switch. Their lever blades do not have the extra little hole punched in them to anchor the inner push plate. Here all of the housings and levers are for US-models with a brake light, unless noted.

Prices: green means new. dark green means used, n.a. means not available. Used items are cleaned, lubed, checked and in good or usable condition unless stated otherwise. Control assembly prices do not include hand grips or electrical switches, unless stated otherwise.

Wrap-around type throttle: Some 1970’s Domino right controls for mopeds have the wrap-around type throttle. The cable wire wraps around the twist tube. The throttle cable exits perpendicular to the handlebar. There is no sliding block, and much less tendency to stick. It requires a “double-ended” throttle cable inner wire with a soldered-on end piece that attaches to the twist tube. That makes the throttle cable not universal, since the inner wire exposed length is pre-set by the lead barrel end at the handlebar.

Sliding-block type throttle: Most 1970’s Domino right controls for mopeds are the sliding-block type. The “universal” or “single-ended” throttle cable inner wire has no upper end piece. It attaches to sliding block with a small pinch screw. The twist tube (barrel) has a spiral slot that moves the sliding block sideways when the tube is rotated. The throttle cable exits parallel to the handlebar.

These throttles need occasional lubrication (oil or grease), or they become sticky and eventually wear out. Because the twist tube is steel and the sliding block is aluminum, it’s the sliding block that wears out the most. Even with lubrication, a worn sliding block causes the throttle to stick, where it does not snap back when you let go. After 1978, they had a helper spring on the twist tube. This made them not stick as much, or not at all.

 


Other Dellorto

March 19, 2021

Dell’Orto ME18-BS

Dellorto ME18-BS

This carburetor was on a 1965-66 Harley Davidson M50, made in Italy by Aermacchi.

∅23 clamp diameter
68 jet, cleaned with 0.027″ wire
40 idle jet cleaned w/0.016″ wire
has idle fuel mixture screw
Z58A needle jet

 

 

 

 

 


Dellorto PHVA

March 19, 2021

Dell’Orto PHVA14

Welcome. This is a “third generation” Tomos carburetor, on US mopeds. It is preceded by two others, the Encarwi A83 on Tomos A3 1974-85, and the Dellorto SHA 14-12P on Tomos A3 1986-91 and A35 1992-06.

 

Dellorto PHVA14 Tomos A55 carburetor four views

 

Dellorto PHVA14 parts

0     N/A     233730 carburetor PHVA 14 DD  right side, no drain
1     $2.00 243115 rubber boot for cable
2     $6.00 243116 adjuster with nut M5-0.75
3     $8.00 243152 throttle cable guide 72º
4     $1.00 243118 carb top screw M5-0.80 x 14
5     N/A     243119 carburetor top cover
6     N/A     set only rubber “figure 8” gasket   see 40 below
6     N/A     set only
paper kind shown, actual kind is rubber
7     N/A     243120 throttle spring Ø12 x 52
    N/A     243121 throttle slide insert
9     N/A     243103 throttle slide #40 Ø15
10   $2.00 243122 needle E-clip for 1.5 clip groove
10a $2.00 phva10 substitute E-clip 1.5 mm
11   $30.0 243104 jet needle A07 2.0-1.0 x 38
11a $8.00 phva11 subst. needle  2.0-1.1 x 38
2.0 needle with 1.5 clip grooveDellorto PHVA throttle needle and substitute
“1.5” clip is 1.3 mm at opening

13   N/A     243125 choke lever bare
14   $4.00 phva14 rubber o-ring 18 x 20 
15   $0.80 243123 screw M4-0.70 x 10
16   N/A     243124 clamp for choke lever
17   N/A     243151 choke Assy 13,14,15,16
18   $8.00 243126 spring idle air Ø5 Ø7 x 9
19   $18.0 243147 idle air screw M5-0.50
21   $8.00 243128 spring idle speed Ø5 Ø7 x 14
22   $18.0 243148 idle speed screw M5-0.80
23   $17.0 243106 needle housing 209GA
23a $15.0 phva23 needle housing 210GA
24   $8.00 243160   main jet 55 M6-0.75 original A55
24a $6.00 D64x052 main jet 52 M6-0.75
24b none   D64x058 main jet 58 M6-0.75
24c $6.00 D64x060 main jet 60 M6-0.75
26   $8.00 243222       idle jet 25 M4-0.70 original A55
26a $8.00 D11600x29 idle jet 29 M4-0.70
26b $8.00 D11600x30 idle jet 30 M4-0.70
26c $8.00 D11600x32 idle jet 32 M4-0.70
26d $8.00 D11600x40 idle jet 40 M4-0.70
28   $6.00 243162 choke jet 40 M5-0.80
30   $25.0 243114 float all plastic bare  
31   $45.0 243149 float with needle valve
32   $35.0 243131 float needle valve  
34   N/A     set only float rubber o-ring  bigger than SHA
3
5   $7.00 243132 float hinge pin Ø2.0 x 19.5
36   N/A     243150 float bowl plastic

Dellorto PHVA Gaskets

Dellorto 52622 PHVA Gasket Set
Right: 6,14,34    Left: others

37  $0.80 027057 screw M4-0.70 x 18
40  $15.0 236460 gasket set 6, 14, 34
   $16.0 D52622 gasket set 6, 14, 34, others
   $5.00 others   gasket set others
45  $26.0 233740 intake silencer assy
46  $5.00 233741 air filter foam
47  $15.0 233748 junction sleeve   see note below
48  $2.00 221584 clamp 32-50

 

 

 

Notes

Junction sleeve 233748 on Tomos A55 models contains an air restrictor. Without derestriction, and with the stock catalytic exhaust, the stock jet is too big. Too much unburned fuel and oil are produced. That causes black goo to drip from the exhaust outlet, and soon clogs the catalytic converter. 

With derestriction, the stock jet size #55 becomes correct. The catalytic exhaust outlet stays super clean. No visible smoke is emitted. Only occasional water dribbles out, just like in modern cars. 

233748 joins carb and air filter

233748 A55 junction sleeve

233738 derestricted

 

 

 

 

 

 

 

 

 

Intake silencer 23340 on Tomos A55 models does more than just reduce noise. It reflects sound waves in a way that recovers or re-captures the mist of fuel and air that flows outward every down stroke of the piston. Remove the air box and a bigger jet is required. Less torque is produced and some fuel is wasted and gets on the rider’s right leg. Besides the magical shape and volume, the stock air box draws air from inside the frame. That air is at a slightly higher pressure than the moving air outside. Tomos engineers made the A55 engine super efficient in order to meet emissions standards in many countries. In doing that, too much power was produced, so restriction was needed to meet power and speed limits.

 


Dellorto Service

March 18, 2021

 

Choke Sticking On: Often the choke sticks on, for no apparent reason. The throttle cable is sometimes too loose to pull up the choke trigger. More often, the choke trigger lever has become bent or twisted. This happens often because great care must be taken to keep the trigger against the side wall when the top assembly (throttle slide, choke trigger, cover assembly) is installed. Before the top screws are tightened, and with one finger holding the top in proper position, it is wise to test the choke by directly pulling on the throttle wire. It should click off at full throttle. Only then should the screws be gently tightened, while holding the top with that finger. If not, then inspect the trigger lever for misalignment, and re-align carefully with small pliers. Sometimes rounding off the side edges helps the trigger lever to not stick also. The last resort is to replace it, but pushing out the tiny hinge pin is difficult. So it is better to straighten it.  

 

 

The Dellorto SHA idle hole is in the silver zinc body, at the base of the brass spray tube

Cleaning a Dellorto idle hole with a tiny #71 drill and a pin vise

Cleaning a Dellorto idle hole with a tiny #71 drill and a pin vise

 

 

 

 

 

 

 

 

Here is the engine side view of a Delorto SHA carburetor. At the base of the vertical brass “spray tube” with one or two holes in it, there is a tiny hole in the silver metal below the brass. It gets overlooked frequently. When it is blocked, the engine will not stay idling for more than a few seconds, but will otherwise run fine if the throttle is kept open.