GS750E Cam Chain Tension

[UKAndy]

My question is can the cam chain tensioner run out of adjustment?

Background: I am still experiencing some slow engine speed top end rattle following an extensive rebuild of the engine. Most of the top end of my engine is new following a failure of my cam shaft bearings. I located a late NOS cylinder head which was rebuilt with new buckets, valves, springs and inlet camshaft. The cam chain was also replaced. I did not replace the cam chain tension guides as they did not show excessive wear. All valve clearances are within spec. The cam chain tensioner was installed correctly and confirmed to be working correctly as per the manual. As the engine is new and has low miles I am still running 5000 rpm max. the top end noise sounds like cam chain slap as when I add revs the noise disappears.

I have removed the cam chain tensioner and it appears to be functioning OK. Whist its out I will replace the seals as it has not been overhauled before.

I know many of the guys racing GS’s in the UK have replaced the auto adjuster with a manual adjuster which appear to have longer plungers.

Any thoughts appreciated.

[Steve]

The big question here is "are you installing it correctly?"

Too many times, we find that it was not. After the plunger is retracted and locked in place, the tensioner is installed. Once installed, you release the plunger, then turn the setscrew until it touches the plunger and BACK IT OUT 1/4 to 1/2 TURN. Then lock it in place with the locknut. The times that I have seen this done incorrectly, the wrench-turner stopped with the "until it touches the plunger", skipped what I have in capital letters, then continued with the "Then lock it in place." That did not allow the plunger to move to take up any slack in the chain.

If you have followed that procedure, you might have other issues, but check first.

.

[UKAndy]

Yes, I have read many of your replies on this subject!

After tightening the lock nut I do the reversing test shown on the bottom of Page 58 of the manual to confirm the tensioner plunger is moving.