Topic: 550f front sprocket issue

[kerryb]

77 550f,  pulled the front sprocket cover to clean and inspect.  Found marks where the chain is rubbing the engine case,  starting to damage the rubber seal in the case.  The chain is a 530, but I dont know what to look for to solve this issue. 
What info do I need;  thickness or offset of the front sprocket (there is no offset)  sprocket says 750 on it.

Thickness of the chain?

What pictures do we need to find the problem?  Chain or sprocket or both?

Thanks for your help, 

[calj737]

Is the chain an o-ring type? If so, they are notorious for being wider that they just begin to erode the seal.

[kerryb]

Apparently I'm the boy who cried wolf here.  I reassmbled all the current parts and put a paper feeler gauge where the damage had occurred.   There was no contact even when pushing the chain sideways.  It seems this damage was caused by a previous chain/sprocket used.
I measured the current chain width at 18.5mm and compared it to an x-ring chain purchased for a '78k 530 conversion project at 22.5mm.  That's quite a difference, I suspect the x-ring chain would rub,.

 Thanks for the help