Hot seized, then free. Rebuild?

[Angoose]

I did a quick and dirty head gasket and seal up on my 74 750. A few hours of riding in and it seized up on my way home. Completely locked. Let it rest a few hours, went back out and it fired right up. Compression still good across all cylinders. The only new issue is an oil leak from the cooling fins on the head, I suspect from the cam tower pucks. I have the motor pulled out, and am deciding if it’s time to do a proper complete bottom and top end rebuild, or just reseal the cam tower and call it good. Anyone know why it might have seized, but now has no remaining issues? Is it worth rebuilding, or since there’s no rod knock and compression is still strong is it good to go? Thanks in advance.

 

[hinksy]

I would try to find out why it locked up . If it overheated , then it`s got to be fuel or oil . When you do the pucks , check for cam journal scouring and oil jet blocks , But I would at least get a hold of a bore scope and see if it chewed out the bores . If you didnt run for too long when it overheated , you probably might be ok bottom end wise , but pull the oil filter and inspect it for glitter . If it is sparkley then dont risk the motor and strip it

 

[Angoose]

I’ve got a feeling it was an oiling issue. My front brake was dragging a little, so there’s a chance maybe the engine was just working too hard, but I doubt that. I’m leaning towards a full teardown, but I’d very much like to not do that if I don’t have to. Didn’t see any sparkles in the oil when I drained it. Gonna cut the filter open this weekend and check it out. At bare minimum I’ll be doing the oil pump and cleaning out all the oil journals.

 

[madmtnmotors]

Not too many things will cause these to overheat. Make sure the crankcase vents are clear and not capped. You really need to know why it overheated.

 

[Old_Crow]

Not too many things will cause these to overheat. Make sure the crankcase vents are clear and not capped. You really need to know why it overheated.

Don't know if it applies, but an inexperienced rider lugging the bike can cause the engine to build enough heat that it'll seize. Very first motorcycle mechanical lesson I learned on a brand new CB175 back in '69 or '70. My old man was pissed as warranty didn't cover it.