Front and rear ISO offsets?

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Jan 10, 2005
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My roadtax ran out last month and with the crap weather I took the chance to take the bike off the road and start on some basic frame measurements. It won't be a "Worlds straightest" but I want to see if I can find the source of the continuing annoying high speed vibes. It's better than it was but only with large clearances and no where near as smooth as the old pre blow up Combat motor.
Question I have is this...Is it normal to find different offsets on the front and rear ISOs? I'd say not but what I found is the front has 0.290" and the rear 0.245". Since the front is fully welded that makes it a Mk3, right?
The bike is a bitsa with late 850 frame and yokes (trees) etc. With just the cradle and front mount assembled in the bare frame and ISO's screwed tight they misalign by about the offset difference. Seems logical. Should I machine the front Norvil adjuster (on the right) and space out with a washer on the left side or could it be that some PO machined a Mk3 mount but didn't get it right? I ask that not knowing the exact differences between the pre Mk3 and Mk3. Mybe I should machine the tube? For what it's worth the exposed tube measures 0.310/0.600 (left and right) from the mount plate.
Any ideas would be appreciated. Thanks.
 
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