Bike won’t run for more than 10 minutes

[Silasr]

I have a 1977 cb750k, and recently my regulator and rectifier went bad. They were original. When it went bad it started out as just the battery not charging and some electronics acting up. On the last ride of the bike with the poor charging I missed a gear and over revved it pretty good. That spike killed the regulator for good and no electronics were working until I just replaced the unit with a eBay regulator/rectifier combo. After the new part everything seemed to be working fine, started up first crank as it did before. But now it won’t run for very long at all and I can’t figure out why. It makes a sucking sound similar to when my carbs were running lean but the plugs are tan. Engine sounds like it is healthy at idle and while still cold so I don’t think I damaged anything internally. I just adjusted my cam chain and valves in hopes that would help but it has not. And my gas tank is venting properly opening the cap makes no difference. Any ideas are appreciated I plan to do a compression test hot and cold in the next couple of days. Thank you

 

[brettp]

Is your bike charging according to spec? Can you find a way to check the charging system at the time it usually dies? I ask because sometimes parts of the charging system act funny as they get hot.

 

[drgnrdr750]

So does it just die or does it seem like it ran out of gas? If it seems like the gas problem check the floats to make sure you have gas flow and it fills the bowl

 

[Remerglobal]

I’ve had stators go bad- and only manifest when the bike is warm.

 

[Silasr]

It turned out to be a bad coil thank you for the responses