Topic: Compatibility of crank case between models…must rebuild by may 28th!!!!

[matchstikman]

Well……I have a 1976 cb750 f1 super sport with a quarter size hole punched through under the drive gear. Upper and lower cases damaged. So are the k and F model cases the same? I’m using all the gears and bearings from the old engine because they’re immaculate. I found a nice one on eBay and it says it’s pulled from a K bike

Thanks in advanced for your input

[willbird]

Back in the day the shade tree folks fixed that with JB weld and kept riding. In the early 70's the 750K needed a riveted together chain, friend of my dad insisted on using industrial chain he got from work and broke a chain and case. JB weld to the rescue. I have heard of other folks doing the same.

[matchstikman]

It would be nice to continue using the original case. I think I just might. Thanks for your input bud!

[calj737]

I would not use JB Weld as suggested. I would have it welded properly. If the cases are fully torn down, then welding it is easiest and best. TIG or MIG works fine. Then you can reuse the stock components and abandon any swap “issues”.

[Ellz10]

I would not use JB Weld as suggested. I would have it welded properly. If the cases are fully torn down, then welding it is easiest and best. TIG or MIG works fine. Then you can reuse the stock components and abandon any swap “issues”.

+1

[Don R]

 I may have a solution, PM sent.