1975 CB750 primary chains and tensioner question

mnvkngs65

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1975 CB750 basket case rebuild in progress (no idea how man miles on the engine, came with 2) (pic). Cracked the cases (first time doing so) and right away noticed the primary chain on the clutch side appears to have less tension than the inner chain (pic) - sounds like this may be normal after reading thru Hondaman's book. I checked the primary chain tension as measured from below and it was in spec (68mm) however the rubber roller looks fairly beat.

1) should I just replace both of the primary chains? First search looks like the are expensive. Are used ones just swapping one problem for another?
2) and a new tensioner because the roller has seen better days?
3) and cam chain since i have the motor apart?

Appreciate the help!
 

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dirtdigger

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Yes replace the primary chains, tensioner and cam chain...as well as the cam chain tensioner wheels. The chains are the weak spot in the motor. Get your parts from Cyclexchange.
 
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