Myrons Mopeds

== 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

 

 

 

 

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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 1978-81 000 Indian AMI-50 (US) xxxx   30 mph

  
1. ’73 Honda PC50K1, 2. ’80 Indian AMI-50 (US), 3. ’73-78 Honda PF50 Amigo line

 

   
1. ’75 Honda PC50K1, 2. ’80 Indian AMI-50 (US), 3. Keihin PA-00A carb, 4. Missing the jet pad #1e.

 

 
1. #0 16100-081-024 Keihin PA-00A carb, 2. #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. left, #0 Keihin PA-M0A carb, 2. right, #0 generic PA-M0A carb

   
1. #1  16010-081-004 carburetor gasket set for PA 00A and 01A
2. #1  16010-143-305 carburetor multi-set for PA 00A, 01A, 03A
3. #1  16010-081-014 carburetor gasket set for PA M0A
4. #1  16010-181-305 carburetor multi-set for PA M0A, 03C, 03D, 03E, 03F

 

quantity
o# ⇓⇓⇓    Keihin  (a)PA-00A  (b)PA-01A  (c)PA-M0A
o# abc price Indian part#  Honda part#    description        specs
00 100  N/A 0000-00-00 16100-081-024 carburetor PA 00A Ø10 E10
00 010  N/A 0000-00-00 16100-099-693 carburetor PA 01A   Ø9 E10
00 001  N/A  E210-00-50 16100-000-000 carburetor PA M0A Ø10
00 111 $75  E000-00-00 16100-000-000 carb generic new Ø10, jet 70 screw-in
00 111 $50  E000-00-00 16100-000-000 carb generic new no top, slide, needle
o1 110 $28 0000-00-00 16010-081-004 gasket solo-set   1a o d e f g h
o1 110 $28 0000-00-00 16010-143-305 gasket multi-set 1a c d e f o h i
o1 oo1 $22 E231-gasks  16010-081-014 gasket solo-set   1a o o o f g h
o1 001 $23 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 $13 E231-####16197-063-004 jet pad disk Ø7.5 x 1.8 
1f  111 $18 E231-02-00 00000-000-000 float bowl gasket Ø1.5 NC50-type
1g oo1 $$2 E231-11-00 00000-000-000 drain screw o-ring 1.5 x 4 (7 od)
1h 11o $$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)
02 110 $21 0000-00-00 16011-881-741 float needle valve  stirrup type
02 oo1 $22 E231-13-00 16155-883-005 float needle 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 11o  N/A E231-01-00 16015-081-004 chamber set 6a 6b 1f 1i
6a 11o  N/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 $$9 E231-19-00 00000-000-000 idle air mix screw M6-0.75 special
7b 111 $$4 E231-21-00 00000-000-000 idle speed screw M4-0.70 special
7c 111 $$7 E231-20-00 00000-000-000 idle air screw spring Ø4.9 x 10
7d 111 $$2 E231-22-00 00000-000-000 idle speed screw spring Ø5.6 x 10
08 1o1 $34 E231-####16022-081-004 valve set 8a 8b Ø13 PA 00A
08 1o1 $00 E231-####16022-HB2-003 new #
8a 1o1 $22 E231-07-00 00000-000-000 throttle slide Ø13 #15A PA 00A
8b 1o1 $12 E231-17-00 00000-000-000 throttle spring Ø10 x 42 PA 00A
08 o1o  N/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″

 

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.

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.    

 

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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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.  

 

 

 

 

 

 

 

 

  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 1w 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 0101 $22 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 0101  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 0101  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

 

 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.

 

 

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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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.

 

 

 

 

 

 

 

  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 $13 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?

 

 

 

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