Timing of cam chain correct? (solved)

[RBoss]

Hi all,

I'm putting together the top end of my engine rebuild and I am not sure if the way I am putting back my cam shaft on the chain is correct.

I am trying to make the top dead centre of cilinder 1&4 correspond with the cam shaft but I am having trouble lining up the holes of the cam sprocket then. This is the best I am making of it now. What would you say?

Also the cam chain is very tight and it is difficult to fit it on the sprocket, i have to turn the tensioner "loose" in order to be able to fit the chain on the sprocket. Is that normal? (It is a new chain)

I have two situations:

1) either the cutout in the camshaft is not entirely horizontal to the top face of the head while the T-mark is correct
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2) the cutout is horizontal but the T-mark is not correct
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Am I doing something wrong?

[RBoss]

Got it! Is was one tooth off...

[Bryanj]

Correct it was 1 tooth out and yes they are a swine to fit when chain is new. You do know that you do not use a screwdriver in the adjuster slot dont you

[RBoss]

Correct it was 1 tooth out and yes they are a swine to fit when chain is new. You do know that you do not use a screwdriver in the adjuster slot dont you

I didn't know that, I suppose one should adjust the tensioner just by loosening the bolt and retightening it again and let the spring to its work? I guess I won't be adjusting mine soon as it is a new one?

[Bryanj]

If you have a new tensioner blade the sideplates of chain wear two grooves into the rubber till rollers touch so adjust at 500 miles after rebuild same as oil change then every 1500.
DO NOT turn engine with a spanner on the big nut at points, lossen adj nut, put weight on kickstsart until crank is about to turn then whilst holding cranck tighten nut

[CB-500]

Hi everyone.. Hopefully you can help I’m coming to the end of an engine rebuild on my CB500K0. I’m having problems with setting the cam chain tensioner, the engine now has a new cam chain and new tensioner blade.The tensioner spring adjustment mechanism looks good and works fine on the bench, the tensioner spring adjustment works fine when fitted in the engine. The issue occurs when the cam chain is fitted to the sprocket on the camshaft, the engine is set at CYL 1 compression 15 degrees past TDC but the tensioner spring adjustment screw will not turn either way (obviously locking nut loose). It appears that the tensioner remains in the fully backed off state set for fitting the chain to the sprocket, it’s almost as if the new chain is too tight which is holding the tensioner in the fully backed off state. Am I reading this thread correctly that a new chain and tensioner blade will do this and needs some running until adjustment is required?
Many thanks

[Bryanj]

New chain and new tensioner can mean little movement, can not repeat too often DO NOT turn that slot in the screw with any tool

[CB-500]

New chain and new tensioner can mean little movement, can not repeat too often DO NOT turn that slot in the screw with any tool

Thanks for the reply.. as per the manual I was expecting the tensioner spring to self adjust automatically from the fully backed off state held for installation. I was concerned when the tensioner spring didn’t self adjust at all when the locking nut was undone. I have only lightly manipulated the adjust screw to have an idea of what the problem could be, but the tensioner remains in the fully backed off state. Unfortunately the service manual doesn’t mention anything about this scenario with new components fitted. If this is normal for new cam chain and tensioner blade is it just a case of backing off the lock nut although the tensioner doesn’t move just retighten the lock nut and run the engine for ‘X’ amount of miles

[Trigger]

If it has been turned or forced, there could be missing teeth, or bent teeth. It is totally automatic. Here is a picture so, if you take the plate off you should see if there is any damage and if it is sliding ok.

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[CB-500]

The tensioner mechanism looks good and turns freely and spring adjusts on the bench the same as when it is installed in the engine. The problem only occurs once the chain is fitted to the cam sprocket and camshaft, My worry is if the new cam chain is too short making it too tight

[deltarider]

Maybe you don't need it, but others may have a look at this video shot by René van Maanen of Honda4.nl. It gives an idea how the tensioner works and why it is, you will not see the bolt turn, when you loosen the locknut to let it adjust; it will move just a fraction.
Mind you, the vid does NOT show how to do the adjustment, it only demonstrates what goes on. To adjust, either do it by the book or like Bryan has posted before. I do NOT recommend adjusting with a running engine like Honda's Owner's Manual CB500K3-CB550K3 suggests.
https://www.youtube.com/watch?v=8qJc6e5pa8M
Courtesy Renë van Maanen - Honda4.nl

[Trigger]

The tensioner mechanism looks good and turns freely and spring adjusts on the bench the same as when it is installed in the engine. The problem only occurs once the chain is fitted to the cam sprocket and camshaft, My worry is if the new cam chain is too short making it too tight

A new chain is tight, if it was one link too short you would never get it on. Come to think of it, i had a new cam chain out of the box once which was a 88 link box but, i did get it on but it turned out to be a 86 link.
Is your front cam blade in the correct way. The can should be between the blade and the inside of the barrels .

[CB-500]

Tensioner blade, guide and chain all fitted and routed as per the manual. Just spoken to Honda- classics (always helpful) they advised that with new components fitted (chain and blade) that the tensioner usually ends up in the tightest state (backed off) adjustment of the tensioner is just designed to allow for wear in the chain, blade and guide. Will be checking tensioner adjustment again after 500 miles.
Thanks for everyone’s help

[deltarider]

I don't have much of an opinion on the design of the CB500/550 tensioner, but the quality they came in, is outright flimsy. It's the part I hate most. Have a look at the pic in reply #8 and you'll understand how little it takes to derail things. Hopefully an aftermarket one is better.

[Seabeowner]

The gearing to the screw head (that you must not turn) is very coarse so the entire rotation of the screw between fully retracted and extended to the point your chain is knackered is probably only about 60 deg CCW.  1/6 of a turn.