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Slow Crank = no start

Radioone

CB750 Enthusiast
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Location
Prineville oregon
1974 cb750 bought last summer fully disassembled. Engine was complete but valve cover and side covers were removed. I now have the bike reassembled, new battery. Compression checks out on all cylinders 120 psi. Engine turns over very slow and won’t start. Starter Solonoid is new and properly wired. Starter works good when removed from engine. I filled the cylinders with transmission fluid and acetone and let sit for a month. Can turn engine over with nut on flywheel/alternator. Still won’t turn over fast enough to start. Now kickstart seems to be jammed although when engaging electric start I can pull kick start through full rotation. Any suggestions? I’m running out of ideas. Engine does have spark. Thanks.
 
120 is pretty low, on the low end of being able to run. Good new battery? The starter could spin fine with no load but not have the power to turn the motor over. How does it spin with the spark plugs out? If it still cranks slow either battery, starter weak or engine internals have some issues. If you can verify battery and starter good I would take engine apart and figure out what is stiff....with the low compression it sounds like it needs work anyway.
 
Thanks dirtdigger. Battery is new and reads good voltage. Starter checks out ok on bench but not sure about performance under load. Today I disconnected the starter solinoid and applied 12 volts directly to starter. Same result turns over very slow. I hate to throw money at the problem but think it’s time to try a replacement starter. I also think the compression will improve if I can get it to crank faster than a sundial.
 
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