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Cam chain adjuster

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toucheturtle:
Hi all,

Decided on a little routine maintenance today but as per usual I seem to have just created a whole world of misery for myself. Adjusted tappets on my CB500K1 and fitted new plugs, before running the bike again thought I'd re-tension the cam chain adjuster.

When I fired the bike up it made a horrible rattling sound on idle and low revs which seems to go away as you increase the revs. The adjusting screw slot is in the horizontal position, is it supposed to be vertical? See photo

Have tried turning the screw but doesn't seem to want to turn more than 45 degrees clockwise. Went through manual procedure of setting crankshaft advancer assembly at 15 degrees ATDC but seems no movement in adjustment screw. I am not aware of damaging anything but does sound like a bag of nails now.

Any advice greatly appreciated,

Andy

honda-san:
That screw is NOT an adjuster! To adjust the can chain tension, all you do is looseb the locknut, with the crankshaft turned to a partcular position, and then re-tighten the locknut (the cam chain tension is automatically adjusted by a spring within the mechanism.
To find the correct crankshaft position, rotate the crankshaft so the T.14 mark aligns with the timing mark on the crankcase, make sure that the number 1 cylinder valves are closed (slack in both #1 cylinder tappets) - if not rotate a full turn and check for #1 tappet slack again. Then rotate the crankshaft a further 15

SteveD CB500K0:
Here's a link to Bryan Jones' patented cam chain adjustment technique.

Not quite by the book but the result of (30?) year's experience...

http://forums.sohc4.net/index.php?topic=369.msg315851#msg315851

Steve

Dave M:
Not quite by the book but works perfectly.

toucheturtle:
Thanks for the advice, I have followed the procedure you describe honda-san, however I have an old Honda 500 manual which describes the engine disassembly process. It advises to:-

"Loosen the lock nut of the cam chain tension adjuster Leave the wrench on the nut), turn the screw fully Approximately 90 degrees) clockwise, and then tighten the lock nut. In this condition the cam chain tensioner is not applying tension to the cam chain."

The diagram shows the adjuster screw slot in the vertical position being turned through to the horizontal position. I'm not aware of moving the position of the screw but now I have noticed it's position I just am not sure if it's in the right position.

Having slept on the problem will check all feeler gaps again, I think it may just be firing on three cylinders as it wont tick over below 2000 revs and klunks over till the revs are raised.

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