Keihin Carburetor Parts family 1, 2

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 16010-163-000
1d 1e 1n 1p     1r

#1 16010-163-004
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″