Chain guard to chain clearance 1972 Commando

Ledslinger

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I've looked at threads discussing chain to chain guard clearance and rubbing, and it seems there are shim washers between the stub axle and brake backing plate that you dan add to get clearance. Two problems with adding shim washers here is that it moves brake shoes away from full contact with the drum, and it makes the sealing flange of the backing plate further away from the groove in the drum.

I'd rather have full shoe contact and less gap between backing plate and drum, so it seems a better place to add a shim washer is between the "rear brake cam bearing and stay" and the swing arm. The only apparent problem here is the flats on the stub axle loose some engagement, but I doubt this is a problem.

I'm talking about a total of two .040" of shim washers, about 1MM. A total of .080" or 2MM.

Thoughts?
 
Both front and back wheels ( by that I mean the tyres ) must be on the frame centre line and in line with each other. The chain goes where it goes.

This does of course assume that both frame and swinging arm are not bent and nobody has messed with the position of the isolastic mounts. Then you really would have a problem.
 
Both front and back wheels ( by that I mean the tyres ) must be on the frame centre line and in line with each other. The chain goes where it goes.

I appreciate this perspective, and it seems an ideal to work for, but it might mean my O ring replacement chain is wider than the original non O ring. I'd rather install a washer to move my chain line .080" to the right than replace a good but wider than original chain.
 
I would be moving the chainguard before considering moving the chainline, unless I knew the chainline was out of line and bring it into line would stop it interfering with the chainguard,
 
I haven't checked my sprocket alignment, but it seems OK by looking at the wear on the rear sprocket. I have some experience with checking chain alignment building my fixed gear bicycle. It isn't easy on a bicycle and they are easier to see and access.

I decided to go back with the single shim that was installed between the backing plate and the stub axle and bent the chain guard a little. Repacked the double row bearing in the drum and installed new drive cushion rubbers.

I was already a mechanic, but Norton ensured I've been converted from being a mortal man. I might be redoing isolastics away from really being a Norton mechanic. Maybe swingarm bushings too. I'm getting closer.
 
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