Keihin Menu

updated 2021-04

Select which Keihin family or section:

== carb ID# ============  M O P E D S  ===========
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

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

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 Express30 mph TS

7. PA 25A-A  1982-83 Honda NC50I, NU50I xxx    25 mph TS

== carb ID#   S C O O T E R S   a n d   M O T O R C Y C L E S
8. PA 29C-D  1984-87 Honda NQ50, NB50 xxxxx   30 mph TS

9. PB 15A-A  1982-83 Honda C70 Passport
xxxxx  xxxxx  OHC

== carb ID# =========  M I N I   C Y C L E S  =========
10. PA   Z502  1968-71 Honda Z50A Mini Trail xx 00 mph OHC
11. PA 655-A  1972-75 Honda Z50A Mini Trail xx oo mph OHC
11. PA 674-A  1970-75 Honda QA50 xxx oooo xx 00 mph OHV
12. PA 03A-A  1976-78 Honda Z50A Mini Trail xx oo mph OHC
12. PA 03C-A  1979-81 Honda Z50R
12. PA 03D-A  1982-85 Honda Z50R
12. PA 03F-B  1986-87 Honda Z50R
13. PA 03H-A  1988-91 Honda Z50R
13. PA 03H-B  1988-91 Honda Z50R
13. PA 03M-A  1992-99 Honda Z50R
13. PA 03N-A  1992-99 Honda Z50R
14. PA 42A-C  2000-03 Honda XR50R
14. PA 42A-C  2004-09 Honda CRF50F

==============  K E I H I N   P A R T S  ===========
Float needles
16. Float bowls
17. Gaskets and O-rings
18. Jets 






Keihin carburetors are used on almost all Honda motorcycles (or copies of Hondas). Here we focus on the 50cc moped, mini-cycle and scooter carburetors mostly from the 1970’s and 1980’s. 

From WikipediaThe Keihin Corporation was founded December 19, 1956 and currently maintains its head office in Shinjuku Ward, Tokyo, Japan. Among the products they are internationally known for is the production of carburetors and fuel injection, and is a major suppler to Honda, and also Triumph, Suzuki, Kawasaki, KTM and Harley Davidson motorcycles. In addition to carburetors, Keihin supplies the automotive industry with engine, transmission and climate control products, including intake manifold assemblies, HVAC assemblies, compressors, valves, solenoids and electronic control units. Keihin’s largest shareholder is Honda Motor Co. Ltd. Keihin first began U.S. manufacturing in 1989. Counting all U.S. locations, Keihin has more than 20,000 employees. Keihin North America’s corporate headquarters is in Anderson, Indiana.

Flange holes 42, 38, 32 mm

Keihin motorcycle carburetors are labeled with a cast-in model ID prefix followed by several numbers and letters that specify the carburetor version for that application. Most of these Honda moped, noped, mini-cycle, scooter and small motorcycle carbs are Keihin prefix “PA”. Other Keihin motorcycle carburetor model codes are PB, PC, PD, PJ, PWK, CV, CVK, VB, VD, VE.

Flange mount: The Keihin PA family of carburetors are flange mount. Flange mount carbs have a diamond shape mounting flange with bolts on either side of the main air hole. The bolt holes can have different spacing.

Carburetor replacement: When replacing a carburetor the new carb must have the same bolt hole spacing. There is a way to get around this by making the bolt holes into slots. With slotted mount holes the flange mount carb is not automatically centered, so it has to be manually positioned in the center as the mount bolts are tightened.