Just picked up a CB750K 10th Anniversary Edition for FREE

[amaskedman]

I put a tad of oil in the plug hole. The compression went up to 120. So it's probably seals. I am you g to double check the high one.

Bottom line, I can't do an engine rebuild and with almost 50k miles, that's what is ultimately required.

So, free bike to someone else hopefully with the skills.

 

[Dave]

I put a tad of oil in the plug hole. The compression went up to 120. So it's probably seals. I am you g to double check the high one.

Bottom line, I can't do an engine rebuild and with almost 50k miles, that's what is ultimately required.

So, free bike to someone else hopefully with the skills.

I'd check the valve clearances before giving up. As the engine wears, the clearance slowly vanishes until the valves are no longer closing all the way.

If you can get the clearances close to correct (a few thousandths loose is actually good for a high mileage engine of this type) you might get good numbers. You might get the same too but, it's worth a shot. If you know nothing about doing a valve adjustment on that engine, learn how before attempting it, not while attempting it. It's not that hard but it's even easier to screw everything up worse.

I had a friend give me a 1979 because it sounded like yours and wouldn't stay running. After a valve adjustment, it ran great.

You can download my messy copy of a shop manual here https://mega.nz/#!oIJD1BoA!QdbWIhNewxnti_eSTcg7sV9tp2k0GLXyoXFVwyu4pgM (28 pdf files)

And AMC49 has posted that you can sign up here http://www.cb750c.com/modules.php?name=Your_Account&redirect=viewtopic&t=301 and find all the tech docs you need.