CB750A no crank

[mrhotrod]

Hello everyone, I am Mrhotrod, I just acquired a CB750A in a trade for a Suzuki GS250, the reason I'm posting is that my bike will not crank over, with a charged battery, in it pushing the starter button results in the gauges dimming and an electrical whining noise, but it doesn't seem like the starter is engaging the crank. Any advice would be appreciated.

 

[amc49]

Charging a battery is an exercise in frustration if the battery is not a known good one.

Will the engine on this 'new' bike turn over by hand? If locked up you can have 10 good batteries and still not turn it over.

You need to establish a better working set of facts there. If starter spinning but engine not turning over then the starter clutch has issues.

 

[mrhotrod]

Charging a battery is an exercise in frustration if the battery is not a known good one.

Will the engine on this 'new' bike turn over by hand? If locked up you can have 10 good batteries and still not turn it over.

You need to establish a better working set of facts there. If starter spinning but engine not turning over then the starter clutch has issues.

Well thank you for your input, but on a hunch a stuck a scope in the cylinders, and I am seeing rust. So I will naturally assume it's locked up, and pull the cover in an attempt to turn the crank, but before I can do that, are there any products you would recommend for freeing up the pistons?

 

[amc49]

I personally don't go there, if engine is stuck it comes apart if mine. I don't try to run dogged out motors like that, I'd rather recoup possibly good parts rather than tear them up in short order.

What if engine is blown up rather than simply pistons stuck? If camchain broke then any moving you do at all is damaging things worse.

If you still insist, WD40 and yank the header pipes to be able to see inside exhaust ports. Once one gets past a certain degree of rust there will be no running decent engine as the cylinder walls will be destroyed and simply tearing it up trying to run it. Some of the trash hits bearings and then kiss it goodbye.