== carb ID# ========= M I N I C Y C L E S =========
9. PA Z502 1968-71 Honda Z50A Mini Trail xx 00 mph OHC
10. PA 655-A 1972-75 Honda Z50A Mini Trail xx oo mph OHC
10. PA 674-A 1970-75 Honda QA50 xxx oooo xx 00 mph OHV
11. PA 03A-A 1976-78 Honda Z50A Mini Trail xx oo mph OHC
11. PA 03C-A 1979-81 Honda Z50R
11. PA 03D-A 1982-85 Honda Z50R
11. PA 03F-B 1986-87 Honda Z50R
12. PA 03H-A 1988-91 Honda Z50R
12. PA 03H-B 1988-91 Honda Z50R
12. PA 03M-A 1992-99 Honda Z50R
12. PA 03N-A 1992-99 Honda Z50R
13. PA 42A-C 2000-03 Honda XR50R
13. PA 42A-C 2004-09 Honda CRF50F
9. Keihin Z50A on #045 1968-69 Honda Z50A Mini Trail up to Z50A-255950
9. Keihin Z502 on #045 1969-71 Honda Z50A Mini Trail after Z50A-255950
Keihin Z50A, Z502
Keihin Z50A, Z502 on 1968-71 Z50A
1968-71 Z50A carb kit
Flange Mount: 32mm hole spacing, 2 x 18 (22 od) o-ring
Main Jet: This carb has a screw-in main jet size 50.
Pilot Jet: It also has a screw-in idle (pilot) jet size 38.
Float Seat: It also has a screw-in float needle seat, replaceable.
Float: no-stirrup metal-tip needle valve, metal swinging float
The Z50A and Z502 carbs are the same except for the needle jet #12 and rubber cable pipe #10.
10. Keihin 655-A on #130 1972-75 Honda Z50A Mini Trail
12. Keihin 674-A on #114 1970-72 Honda QA50
12. Keihin ceto and #129 1973-75 Honda QA50
Keihin 655-A on 1972-75 Z50A
1974-75 Z50A carb kit, missing the drain plug o-ring and jet pad disk.
1970-73 Z50A carb kit also had a float seat and a float seat washer.
Flange Mount: 32mm hole spacing, no o-ring groove on carburetor. Instead the o-ring groove is on the intake manifold. Since the 2 x 18 (22 od) intake o-ring is not part of the carburetor, it is not in the Honda gasket set 16010-114-004, or the multi-app set 16010-114-305.
Main Jet: This carb has a “long” press-in jet, with a rubber pad disk under it.
Pilot Jet: The idle jet is not replaceable. It is inside the upper end of the brass tube, pressed into the main body, on the engine side of the main jet.
Float Seat early: The 1970-73 carburetor had a screw-in float needle seat, that was replaceable, like in the illustration.
Float Seat late: The 1974-75 carburetor did not have a replaceable float needle valve seat. The seat was part of the main body, and must be cleaned and polished with a spinning Q-tip.
Float: no-stirrup metal-tip needle valve, swinging float 16013-114-004
Top Cap: M18 x 1.0 thread
Drain screw: 1970-73 chamber set 16015-114-004 had a M4-0.7 thread drain screw with a 2 x 4 (8 od) o-ring. 1974-75 had a M6-0.75 thread drain screw with no o-ring. 1976-78 had a M6-1.0 thread drain screw with a 2 x 2.5 (6.5od) o-ring. 1979-later had a 1.5 x 4 (7od) drain screw o-ring.
Keihin 655-A, 674-A
quantity
o# ⇓⇓ (a) 655-A (b) 674-A
o# ab price Honda part#x description xxx specs
o0 10 N/A 16100-120-010 carburetor 655-A Ø?? ’72-75 Z50A
o0 01 N/A 16100-000-000 carburetor 674-A Ø?? ’70-75 QA50
o1 11 $24 16010-114-004 gasket solo set 1d 1e 1h 1n 1p 1r
o1 00 $24 16010-114-305 gasket multi set 1d 1e 1h 1n 1p 1r 1q
1d 11 0$2 16176-551-004 main jet o-ring 1 x 3 (5 od)
1e 11 $13 16197-063-004 jet support disk Ø7.5 x 1.8
1h 11 $$2 00000-000-000 intake o-ring 2 x 18 (22 od)
1n 11 none 16173-063-004 float bowl o-ring 1.5 x 40 (43 od)
1p 11 0$5 16171-044-004 top rubber washer 10 x 15 x 1
1r 11 0$5 16175-001-004 drain screw o-ring 2 x 4 (8od)
16010-114-004
1972 Z50A drain screw
11. Keihin (10 mm) PA 03A-A on #130 1976-78 Honda Z50A Mini Trail
12. Keihin (11 mm) PA 03B-A on #181 1979-79 Honda Z50R up to 5022291
12. Keihin (11 mm) PA 03C-A on #181 1979-81 Honda Z50R after 5022291
12. Keihin (11 mm) PA 03D-A on #181 1982-85 Honda Z50R
12. Keihin (11 mm) PA 03F-B on #181 1986-87 Honda Z50R
In 1979 the model name changed from Z50A to Z50R, and the name Mini Trail was dropped.
#0 16100-130-642
Keihin PA 03A-A
for 1976-78 Z50A
from cmsnl.com
#0 16100-165-004
Keihin PA 03B-A
for 1979 Z50R
#0 16100-165-014
Keihin PA 03C-A
for 1979-81 Z50R
from cmsnl.com
#0 16100-181-751
Keihin PA 03D-A
for 1982-85 Z50R
#1 16010-181-832
Keihin PA 03F-B
for ’86-87 Z50R
from cmsnl.com
1976-78 Z50A carb kit
D348 thick needle, #58 push-in jet.
The drain screw and jet support pad are missing.
1979-81 Z50R carb kit
D117 thin needle, #58 screw-in jet. Left to right: drain screw, needle jet (emulsion tube), idle air screw, idle speed screw, float needle
Flange Mount: 38 mm hole spacing 1976-78. 32 mm hole spacing 1979-87.
Pilot Jet: The idle jet is not replaceable. It is inside the upper end of the brass tube, pressed into the main body, on the engine side of the main jet.
Main Jet: For some reason in 1979 Honda wanted to make their jets tamper-proof. It’s funny that they went from one extreme to the other, from jets that fall out too easy, to jets that never come out. Both the NC50 and the Z50 changed to “fixed” jets (not replaceable) in late 1978 and 1979. After 1981 the jet was a screw-in, thankfully, like in the illustration
Float Seat: This carb does not have a replaceable float needle valve seat. The seat is part of the main body, and must be cleaned and polished with a spinning Q-tip.
Carb Kit: Beware of low-cost carburetor kits. In the kit at the right several things are wrong or made badly. 1) it is missing the press-in jet pad disk, 2) the jet o-ring was too big to allow the jet to press in. You can see it seems big in the photo. It was size 1.5 x 4 instead of 1 x 3, 3) the float needle was longer than stock, and the wire stirrup was bent badly in two ways. The throttle (jet) needle was D117 thin instead of D348 thick.
Float: In 1979 the float and float needle changed, from stirrup-type needle valve with black foam float, to no-stirrup needle valve 16155-883-005 with white plastic float 16013-147-004. Like before, the float needle has a rubber cone upper tip and a spring-loaded lower tip.
Float Bowl: The 1979-later float bowl no longer has a press-in jet support pad disk 7.5 x 1.8mm.
16010-081-004
#1 16010-143-305
#1 16010-081-014
#1 16010-165-621
#1 16010-181-305
PA 03A, 03B, 03C, 03D, 03F
quantity
o# ⇓⇓⇓⇓ PA(a)03A-A (b)03B-A (c)03C-A (d)03D-A (e)03F-B
o# abcde price Honda part#x description xxx specs
o0 1o0oo N/A 16100-130-641 use 16100-130-642
o0 1o0o0 N/A 16100-130-642 carburetor PA 03A-A Ø10 x 38 ’76-78 Z50A
o0 o1000 N/A 16100-165-004 carburetor PA 03B-A Ø11 x 32 ’79-79 Z50R
o0 o0100 N/A 16100-165-014 carburetor PA 03C-A Ø11 x 32 ’79-81 Z50R
o0 oo010 N/A 16100-181-751 carburetor PA 03D-A Ø11 x 32 ’82-85 Z50R
o0 00001 N/A 16100-181-830 16100-181-831
o0 00001 N/A 16100-181-832 carburetor PA 03F-B Ø11 x 32 ’86-87 Z50R
o1 1o000 $28 16010-081-004 gasket solo-set 1a o d e f o h i
o1 10000 $28 16010-143-305 gasket multi-set 1a c d e f o h i
o1 01100 $22 16010-081-014 gasket solo-set 1a o o o f g h
o1 00011 $23 16010-165-621 gasket solo-set oo o o o f g h o l
o1 01111 $23 16010-181-305 gasket multi-set 1a o o o f g h o l
1a 1o000 $$3 00000-000-000 top rubber washer 10 x 18 x 1
1d 1o0o0 0$2 16176-551-004 main jet o-ring 1 x 3 (5 od)
1e 10000 $13 16197-063-004 jet support pad disk Ø7.5 x 1.8
1f 11111 $18 00000-000-000 float bowl gasket Ø1.5 NC50-type
1g o1111 $$2 00000-000-000 drain screw o-ring 1.5 x 4 (7 od)
1h 11011 $$2 00000-000-000 intake o-ring 2 x 18 (22 od)
1i 10000 0$2 16175-260-004 drain screw o-ring 2 x 2.5 (6.5 od)
1l 01111 0$4 16110-181-831 top rubber washer 13 x 19 x 1
02 10000 N/A 16012-130-640 needle set 03AA
02 010o0 N/A 16012-165-014 needle set 03BA use 16012-181-831
02 00111 N/A 16012-181-831 needle set 03CA, 03DA, 03FB
03 1o000 N/A 16013-099-691 use 16013-143-620
o3 1o000 $46 16013-143-620 float set 3a oo 3c 3d black stirrup
o3 o1111 $28 16013-147-004 float set oo 3b 3c 3d white regular
3a 1o000 N/A 00000-000-000 float bare, solid black foam stirrup
3b o1111 $21 00000-000-000 float bare hollow white plastic regular
3c 11111 $$4 00000-000-000 hinge pin substitute Ø2 x 18.5
3d 11111 $$3 0-93600-04006 hinge screw M4x6 sunk phillips
o4 11100 N/A 16014-130-640 top set with pipe 4a 1a M18-1.0
o4 00011 N/A 16014-GB1-912 top set with pipe 4a 1l M20-1.0
05 1o000 N/A 16015-130-640 chamber set 5a 1e 1f 5b 1g
05 o1110 N/A 16015-099-691 chamber set 5a oo 1f 5b 1g
05 o???1 N/A 16015-130-641 use 16015-130-641
05 o???1 N/A 16015-165-621 chamber set 5a oo 1f 5b 1g
6a ????1 N/A 16016-165-621 use 16016-165-505
6a ????1 N/A 16016-165-505 idle air screw set
6b ????1 N/A 16208-GC8-004 idle speed screw set
07 ????? N/A slide set
09 ????? N/A rubber cable pipe cover
10 1o0oo N/A 16011-143-620 use 16011-881-741
10 1o0oo $21 16011-881-741 float needle valve stirrup
10 o1111 $22 16155-883-005 float needle valve regular
11 22222 0$1 93892-04012-08 screw & washer M4x12 pan phillips
14 10000 $16 99201-081-0580 main jet push-in #58 0.0228″
14 01100 N/A fixed needle jet and main jet pressed in 0.0228″
14 00011 0$7 99101-187-0580 main jet screw-in #58 0.0228″
18 11111 N/A (not sold separately) idle jet press-in tube 0.015″ pinhole
12. Keihin PA 03H-A on #GW8 1988-88 Honda Z50R up to JS900485
15. Keihin PA 03H-B on #GW8 1988-91 Honda Z50R after JS900485
15. Keihin PA 03M-A on #GW8 1992-93 Honda Z50R
15. Keihin PA 03N-A on #GW8 1994-99 Honda Z50R
#0 16100-GW8-682 Keihin PA 03M-A
#0 16100-GW8-305 Keihin PA 03N-A from cmsnl.com
Flange Mount: 32mm hole spacing
Main Jet: screw-in #58, M6-0.75
Float: no-stirrup type white plastic 16013-147-004, needle valve 16155-883-005
Top Cap: M20-1.0 thread
Idle Mixture Screw: For the entire Z50A and Z50R year range 1968 to 1999, the idle mixture screw was an air type, not a fuel type. An idle air screw blocks an air tunnel, so tighter is less air (richer). An idle fuel screw blocks off a fuel tunnel. So tighter is less fuel (leaner).
1992-98 Z59R carb kit
#1 16010-181-831
for PA 03H 03M 03N
#1 16010-181-305
for PA 03H 03M 03N
#5 16016-GW8-672
This idle air screw looks
like an idle fuel screw.
Keihin PA 03H-A, PA 03H-B, PA 03M-A, PA 03N-A
quantity
o# ⇓⇓⇓⇓ Keihin PA (a)03H-A (b)03H-B (c)03M-A (d)03N-A
o# abcd price Honda part#x description xxx specs
o0 1000 N/A 16100-GW8-671 16100-GW8-672 carburetor PA 03H-A 1988 Z50R up to JS900485
o0 0100 N/A 00000-000-000 16100-GW8-673 carburetor PA 03H-B ’88-91 Z50R mix screw changed
o0 0010 N/A -680 -681 000 16100-GW8-682 carburetor PA 03M-A ’92-93 Z50R
o0 0001 N/A -780 -791 000 16100-GW8-792 carburetor PA 03N-A ’94-99 Z50R
o0 1111 N/A 00000-000-000 16100-GW8-305 multi-carb PA 03N-A replacement
o1 1111 $23 16010-181-831 gasket solo-set o0 1f 1g 1h 1l
o1 1111 $23 16010-181-305 gasket multi-set 1a 1f 1g 1h 1l
1f 1111 $18 00000-000-000 float bowl gasket Ø1.5 NC50-type
1g 1111 $$2 00000-000-000 drain plug o-ring 1.5 x 4 (7 od)
1h 1111 $$2 00000-000-000 intake o-ring 2 x 18 (22 od)
1l 1111 0$4 16110-181-831 top rubber washer 13 x 19 x 1
02 needle set
03 float set
04 chamber set
05 idle air screw set
06 slide set
07 idle speed screw set
09 top set
10 float needle
11 float bowl screw
12 drain hose
13 drain hose clamp
14 main jet
13. Keihin PA 42A-C on #GEL 2000-03 Honda XR50R
16. Keihin PA 42A-A on #GEL 2000-03 Honda XR50R
16. Keihin PA 42A-A on #GEL 2004-09 Honda CRF50F
In 2000 the Z50R was replaced by the XR50R. The carburetor remained mostly the same.
Links to Images:
2000 Honda XR50R carburetor PA42A-C
2008 Honda CRF50F carburetor The gasket for this was in use for over 34 years!
This carburetor looks the same as the previous Z50R ones, except the flange is thicker and has square corners, not rounded.
Flange Mount: 32mm hole spacing, thicker with square corners
Chinese re-makes of this carburetor are common on the internet, at incredibly low prices. Read several reviews before buying one. Try to re-use the original Keihin.
In 2004 the XR50R was replaced by the CRF50F. The carburetor remained mostly the same.
Service: Here is a good article about how to remove and clean the non-replaceable idle (pilot) jet.
https://thumpertalk.com/forums/topic/1047667-clogged-pilot-jet-on-a-crf50-success/
The CRF50F idle jet in that article did not crush when gripped lightly with a vise grip pliers. But some pressed-in idle jets have thin walls, or have a tighter fit that needs heavy clamping. Those require a close-fitting drill bit or solid wire, be placed in the hole first, to prevent crushing the tube with the vise grips. It’s a good idea to do that always.