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Motorcycle Repair/1978 honda 750K


Bill I'm the one that had the points for the #1-4 points were sparking. I replaced the coils and the points and that problem is good now.
But now I have a problem with what I think is fuel related. It starts and idles good, but when you are riding it fades out like it's starving for fuel then it starts to run good again. This comes and goes. I ran a can of sea foam through it checked the filter and fuel shut off there is plenty of fuel coming out of the shut off. If you have the shut off turned to the main tank or reserve it makes no difference.
 Any suggestions Thanks Ed

Ed, I assume that you removed the screen up inside the gas tank for inspection?  If so and the fuel system seems to be clean and clear of blockages, then I would look back to the gas cap vent hole. The fuel tank has to be vented for fuel to flow correctly. Evaporating gasoline fumes can build up inside the cap and reduce the vent hole size down to near zero. for reference on the filter.

You could also have restrictions in the shared fuel line connections between carburetors. Check for air leaks at the carburetor intake manifolds. These bikes had EPA carburetors on them and are jetted lean from the factory. If you have changed the air filter system or the exhaust, it can put the jetting over the edge causing lean surging. With today's fuels, I would plan on going up a step on the main jets and perhaps shim the slide needle to richen it up some more.

Look at the spark plugs to see what they will tell you about jetting conditions.

Glad to hear that the electrical issues are resolved now.

Bill Silver  

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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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