CB750 Motor Melt

[dhubb]

Hey all, I'm new to the forum. I'm in the process of tearing down a K1 motor and when I could get the case to come apart, I realized the case near the chain sprocket appears almost like it has been melted. Has anyone seen anything like this before? The motor had a broken chain tensioner which is why I was tearing it down to begin with.

If I'm right, is this case shot?

Thanks,
Dustin

 

[dirtdigger]

Case has been welded from a broken chain. looks like the chain has rubbed after the repair as well. Possibly they did a poor repair not leaving enough room for the chain or running way to big of a front sprocket. You will have to determine what is causing the rubbing since the repair.

 

[user8086]

Weld

 

[dhubb]

Thanks for the reply. That makes perfect sense. With the weld there I can’t crack the case to rebuild. Seems like I’m best just getting another motor.

 

[cfairweather]

I think you will be fine with this case. You may have to reweld it, but after you clean up the weld joints, it will be fine. There are many on the road that have been repaired.

 

[dhubb]

I’ll probably sell it bc I don’t have the tools to cut open the weld. Good to know someone could use it though. Thank you!

 

[dirtdigger]

I cant believe it was welding all as one piece. Thats unfortunate. You could just buy a different set of cases and use the internals plus new bearings.