exultant801

just bought a 1976 cb750k, drove about 300 miles home without any problems at all.

really clean, about 19k miles on it. about a week later 1st and 2nd gear started sputtering and struggling when i kicked in. kind of like when you upshift too soon from like, 1st right to 3rd and it struggles to keep going...but 1st and second are doing it every time.

also, its idling funny(not consistent and steady)

its not the spark plugs.
pretty sure its not a carb issue.
not a timing issue.

i was told it could be the spark plug cables are rotted and stiff.
or the coils?
also told it might just need a valve adjustment.

had some funny electrical issues here and there as well, but not sure if its related.


anyone dealt with these kind of issues before???

any feedback, much appreciated!

shovelicious

1. What is each valve lash?
2. What is the compression?
3. Where are the points positioned?
4. Where are the carbs in their sync positions?

Follow the above sequence in order:

1. .002" for Intake/.003" for exhaust lash clearances.
2. Compression is anything over 120psi and must be within 15% of each other or rebuild what is worn with the 15% cylinder(s) giving you a poor idle. First find the lash being correct before you take a compression check. A tight valve with a simple adjust just tore your engine down for nothing you do not inspect this first.
3. If running stock points; they have a range between .012" to .016" of an air gap. If you can get worn points to break at the "F' mark, means, the points are good enough to set the timing. Ideal air gap is .014" with new points.
4. Idle is all about equal compression. The syn is nothing more than finding equal air passing under the slide by using a carb sync tool like a manometer.