Topic: cam chain tension bar all the way in...

[setdog]

Cb750 k5

If my cam chain tension bar is all the way in but shows no real improvement in engine rattle
Would it be reasonable to assume the tensioner system or the chain has degraded beyond usefullness and might require replacement?

[stewonepot]

yes probs with the rubber wheel. A mite too old!
regards Stew

[MCRider]

Curious, how do you know its all the way in?

[setdog]

Curious, how do you know its all the way in?

good question, im guessing it is. i dont have much experience with this. 

 the bar has that little flange at the end where the screw catches, and i set the screw loosely, but still catching the bar, before reinstalling the unit.  after entire unit was attached i tried to push the bar through the hole in the end to see if i had any movement, no movement.   im an amature at this and im guessing this means the bar is in the fully extended position.  im also assuming that if its fully extended and no difference in engine noise, then either im just doing it wrong, or the tension system isnt performing as intended and something may just be too worn out to work as it should. 

didnt make sense to have screw not catch the bar, but sit behind the bar,...maybe thats how it works...that would be only one setting and not anything to adjust. 

ill have to have to another go before i can declare problem solved tho.

[MCRider]

I think you got it all right. But as the engine turns forward the chain gets tight and loose depending on the bias of the valve springs to roll the cam forward or backwards. So, as you've got it, the tensioner bar, unclamped by the lockbolt, will track the chain, moving in and out with the slack or tension of the chain. And it will be noisy.

What you must do, and the manuals all explain this, is set the engine at a spot where all the slack in the chain is on the back run. IF the plunger bar is free, and yours seems to be, the spring will push it into the chain. Then tighten the lock bolt, which hits the machined flat spot of the tensioner bar.

The position of the engine should be 15deg ATDC on 1-4. Roll the engine forward till you see 1--4 thru the peep hole on the points plate. Continue rolling it forward till the left side of the spring post lines up with the raised timing mark on the crankcase. That's 15deg ATDC. Since you know how, push on the tensioner bar thru the hole in the back of the tensioner body with a small screwdriver or allen  wrench. That will assure max adjustment. Release the pushing, and snug down the lock bolt.

Now fire it up and listen.

[flybox1]

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[MCRider]

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Very nice Flybox. The text is all correct But isn't the sketch a little off? I thought the T/F marks rolled completely past the timing marks before the spring post came in view. I don't think they all appear together as in that sketch.?

Been a while since I set mine.

[flybox1]

yes, you are correct.   most wouldn't pick up on that 
the main point of the drawing is how the timing mark aligns with the spring peg to easily find 15deg past TDC.

its also good to keep pressure on the big nut so it doesn't roll backward, removing the slack from the chain as you are setting the tensioner

[MCRider]

yes, you are correct.   most wouldn't pick up on that 
the main point of the drawing is how the timing mark aligns with the spring peg to easily find 15deg past TDC.

its also good to keep pressure on the big nut so it doesn't roll backward, removing the slack from the chain as you are setting the tensioner

Its been a while, but I've done hundreds of them. (Seems)

You're right can't hurt to keep pressure on the nut.