Motorcycle Repair/honda c50


hi I have just restored a 1968 Honda c50 it was running yesterday but it will not start today it has a strong spark,i have cleaned out the carb in a sonic cleaner and rebuild it but it will not start would you have any idea thanks gary.

Gary, the basics of the 4 stroke engine are

Fuel at correct mixtures
Spark at the right time
Air to mix the fuel inside the carburetor..

You should be measuring about 150+ psi compression.. if not check your valve clearances next

Make sure your spark is coming at the right time and is steady during cranking. Intermittent spark at the plug is usually a sign of either a loose wire connector, bad condenser or weak coil... or low battery voltage.

Check carburetor for all jets in place, mixture screw set to specs, slide needle clipped and secured. Look at intake manifold gaskets/o-rings and check for any stripped thread holes at the cylinder head that allows the manifold to work loose.

Try running without the air filter hooked up.

Sometimes the spark plug will fuel/oil foul on initial startup, so try a fresh new plug if all else fails. The spark plug cap should either be zero ohms or 5k ohms at the most.

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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