Topic: 81' CB650 Cam chain adjustment problems

[rfrench924]

Hello All,

I have searched through all forums before this post but cannot find anything related to the CB650 cam chain adjustment issues. It seems that my adjuster has become stuck and will not tighten. I have tried to loosen the lock nut (#10) and rotate the crankshaft slowly using a socket while tightening this lock nut back in place, but this has not helped. Engine noise is still there.

I have read some posts of actually turning the bolt itself with a screwdriver but i think this is in relation to different models (550's etc). Does anyone have any experience with the cam chain adjuster as pictured below? Can i take the bolt above (#11) out and maybe push on the adjuster? Can i completley remove (#11) and push the bolt inwards to adjust?

Any info would be great. I rarely have to post becuase all this great information is usually available by searching. There just doesn't seem to be many 650 guys out there!! Where are you all?!

[griff6-5-zero]

I'll bump it for you!

[rfrench924]

nothing? I was hoping to ride tomorrow.

I guess i'll try some things on my own

[Frankenkit]

You're looking at removing the lock nut (10)... but don't just back it off a bit.  Another thing you could try is backing it off some while at the lowest idle possible, then tightening it again.  Try shooting some WD-40 around the bolt, might help if the spring etc is stuck (?)

but then again, these bikes have effing terrible cam chain adjusters and chains, so either could be worn beyond any kind of servicing. 

I'm having the same problems with mine, except I can get mine tight to the point of relatively little noise, but it's loud again after riding 20 mi. P

[martino1972]

you can try by carefully give it a wack when #10 is loosened off.....try that while turning engine by hand.....

[WFO]

how many miles on the bike?

[cb650]

Yes try pushing in on the nut whil loose. sometimes the internals get stuck and need help.
I've been adjusting mine with the starter and the kill switch off.  Usually do it during a plug change to so they are all out.  Has anyone been in the top end?  Its not hard to miss the notch that the bottom of the adjuster sits in. 

[WFO]

Yes try pushing in on the nut whil loose. sometimes the internals get stuck and need help.
I've been adjusting mine with the starter and the kill switch off.  Usually do it during a plug change to so they are all out.  Has anyone been in the top end?  Its not hard to miss the notch that the bottom of the adjuster sits in. 

I agree that was a pain in the ass to make sure it was back in that slot.

[Hush]

Are you sure your noise isn't carbs out of sync?
These 650's make a terrible noise if the carbs are not balanced, mine quietened right down after I got the shop to sync carbs.
I hardly notice any difference when I do the adjustment on my cam chain, would be nice to have an indicator of how much freeplay was removed or something eh.

[pit monkey]

Have you tried to do the tension adjustment per the manual.  Per the manual you loose the lock nut and then while turning the crank clockwise with socket you torque the lock nut to 7 to 10 ft-lb. 

"The tensioner will automatically position itself to provide the correct tension when the lock nut is loosened." sayth the manual... 

I did that way and other than wishing for an extra hand  it seemed to work.  I don't remember checking to see if the tensioner was loose when the lock nut was backed off.  I kinda of think that it wouldn't be given that there a spring that doing the adjusting.

[rfrench924]

The bike has about 30k on it.

I recdently did a top end rebuild. New rings, honed cylinders and replaced gaskets and o-rings. I did my buddies last year and never had a problem getting the tensioner into that notch.

I tried first with the bike running. I could queit it down alot but only if i barley tightened the lock nut. I'm wondering if doing this while running maybe jameed something up in there.

I'll back the lock nut off a bit today and see if i can push the bolt in a bit. I know on my buddies 650 we almost lost that bolt inside of the case so it should move.

Thanks for all the helpful tips. I'll also take all the plugs out and adjust while turning by hand. I did try this already but i'm hoping its just stuck.

Lets say i did miss this notch, what do i need to unassemble to get it back in?

thanks again

[cb650]

All but they cyls.   first 2 topends I did no problems.  3rd took 3 times before I got it.  I think you can see it with the pan off.

[Frankenkit]

I'm watching this because my bolt wasn't moving much either, and I don't know if the guy who helped with the top end did it right.

[WFO]

Hmmmmm i was looking at my tensioner when it was out and on mine atleast all the movement is inside the length of the tensioner itself pulling on a spring so iam kinda of confused on what you guys are expecting to see from the bolt on the outside? Per the manual you put it on TDC where if there is any slack in the timing chain that's where it will show up, after losing the bolt and slowly turning the crank clockwise then slowly tighten the bolt the tensioner should move out and tighten up the chain. ( the above diagram looks just like mine) and mine is a 82.

[Frankenkit]

Why TDC, if you're turning the crank, anyway? 
My honda service manual says :

Adjust the cam chain tension with the ignition switch off, transmission in neutral and the motorcycle on its center stand.

Remove the pulser generator cover.
Loosen the cam chain tensioner lock nut.
Tighten the cam chain lock nut while slowly rotating the crankshaft clockwise.

Note: the tensioner will automatically position itself to provide the correct tension when the lock nut is loosened.

Install the pulser generator cover

[Hush]

WFO and Kit you both get a chocolate fish, that is the correct sequence for adjusting cam chain tensioner.
Weather or not it actually tensions the cam chain is debatable!
Guess we gotta cross fingers on that one, I don't notice the cam chain rattle anymore, not sure if I'm just used to my motor running now or if I got the adjustment right?

[martino1972]

Guess we gotta cross fingers on that one, I don't notice the cam chain rattle anymore, not sure if I'm just used to my motor running now or if I got the adjustment right?

or can't you hear it anymore because the rest of the bike is rattling so much....

[Hush]

I'm tempted to buy a welder so I can button up everything that rattles and replace my knackered rear shocks with a set of old anchor chains.

[martino1972]

I'm tempted to buy a welder so I can button up everything that rattles and replace my knackered rear shocks with a set of old anchor chains.

that would be a great idea...!!!!!! no more funny corners,no more noises.....man that's an awesome idea.....***why didn't I think of that..****   

[cb650PK]

Full face helmet + ear plugs are the only remedies for cb650 cam chain rattle. Slight hearing loss due to advancing age helps a little. I believe there are very few cases of the damn thing actually breaking.

[WFO]

WFO and Kit you both get a chocolate fish, that is the correct sequence for adjusting cam chain tensioner.
Weather or not it actually tensions the cam chain is debatable!
Guess we gotta cross fingers on that one, I don't notice the cam chain rattle anymore, not sure if I'm just used to my motor running now or if I got the adjustment right?

I know what ya mean after i put mine back together you have to sqeeze the tensioner in all the way or you can't get the cam chain over the cam sprocket and the chain was loose so i know it does do something it's a very small movement for the tensioner to take up the slack but you can't see it and the bolt on the outside isn't going to do anything and that was kinda my point.