Inner primary case wear...

I was disassembling a parts bike and found this wear on the inner primary chaincase.
The steel washer/and shim between the inner case and mounting stud was missing causing the inner case to be pushed inward when tightening the primary cover nut.
The steel sliding felt seal disc also had nearly worn through.
The front side of the inner cover was slightly cracked where it bolts to the crankcase due to the twisting.
The rider HAD to hear the chain rubbing on the inner case! Note the wear mark from the swingarm cover.

I think that checking the primary drive side for all the proper alignments is critical for a good reliable bike.

Yep that's not how it's supposed to look, could be why they gave up on it and how it became a parts bike. But you're right , they had to have heard/noticed that

About half of the Commandos I've disassembled had cracking at the front and wear at the back. It's a common bodge.

grandpaul said:

About half of the Commandos I've disassembled had cracking at the front and wear at the back. It's a common bodge.

Click to expand...

Yes, bodge! Inner primary shimming 90%, Gearbox alignment 5%, misc 5% . IMHO

The bodge typically occurs when the primary chaincase is removed for whatever reason, the disassembly was not careful, and the shim didn't get replaced. As soon as the center stud receives any tension, the distortion and cracking will occur at the 3 bolts holding the inner case to the crankcase.

Something to look for when inspecting a bike with unknown history.

Bob Z. said:

Something to look for when inspecting a bike with unknown history.

Click to expand...

That is far worse than the primary inner having a crack...