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Motorcycle Repair/Honda CB750FA 1980


More problems.I now find my 750 has 900 Keihlin carbs VB51s
They have jets as per 750 and standard airbox but at tickover its very rich.Am I wasting my time trying to run on these carbs?Help most appreciated.

Bill, I don't think the carburetor venturis are any larger on the 900 carburetors, as the piston valve part number is the same for both models. Calibrations are different, though..

primary main jet/main jet/idle jet
(if used)
068/102/35 cb750 16012-425-601 needle

068/98/42  cb900 16012-438-003 needle

So you need to see what calibrations you have on the carbs on the bike and adjust accordingly.

Bill Silver  

Motorcycle Repair

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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