Cam movement?

[monkeyboy]

Morning. My 1150GSA left cylinder is making really nasty noises. It sounds very 'cam chainy' so I initially got a new tensioner. The noise didn't go away, or maybe died down a little. I took the tensioner out again and the piston had seized solid - weird - so I worked it and got it moving properly, soaked in a bath of oil, refitted, no significant change. Took out the tensioner, solid again and this time I can't get it moving. I re-fitted the old style original one and it now the noise is very bad is definately of the "I'm going to fail in the near future" variety. I've recently had the valve gear off to check the chain guides are 100%, not snapped/melted/whatever and they look OK. So now I'm going to have to take the head off and look deeper.

Thing is, I've put a M10 hex in the end of the cam bolt to undo it and there is a lot of movement clockwise/anticlockwise. Looks to me like the only thing stopping the movement is the chain. To my simple mind, there shouldn't ever be any 'wiggle' movement in a cam when it is all assembled. It should always be under tension from the valve gear stopping the cam rotating at all. Obviously the engine is at TDC and you can wiggle the followers.

Am I missing something? I'm going to have to take the head off later today anyway so maybe then I'll be able to work it out but maybe it's the source of the impending doom for the left cylinder.

If is IS ok then I'm buggered if I know whats going on. The cam chain tensioner piston is locking I think because it is operating at beyond its maximum length due to the slack in the chain and the constant tapping back and forth against the housing is buggering it.

I'd be very interested in any thoughts or advice on this grey rainy day

 

[monkeyboy]

OK - taken the valve gear out and can see that the cam allows a lot of 'non-reactive' movement at that point which is what I would expect around TDC - its just the ease with which I could move the cam round - even with the tip of a small screwdriver - I guess I just expected more resistance but with the engine at TDC the rockers aren't touching the valves and therefore there is no pushback onto the cam. My bad

 

[monkeyboy]

Do cam chains stretch?

I've taken the head off and still can see absolutely nothing wrong. Given that I'm almost sure my problem is lack of cam chain tension, that I've changed the tensioner to the upgraded piston type that it has subsequently buggered (twice) then my only thought is that the cam chain has stretched. The bike has done 100k, quite a lot of them hard miles in very very hot conditions.

Anyone heard of them stretching? The chains are quite long so I suspect it would only take a small percentage increase to give me my problem.

If they do - are they a B'stard to replace?

 

[taffyflytyer]

I've taken the head off and still can see absolutely nothing wrong. Given that I'm almost sure my problem is lack of cam chain tension, that I've changed the tensioner to the upgraded piston type that it has subsequently buggered (twice) then my only thought is that the cam chain has stretched. The bike has done 100k, quite a lot of them hard miles in very very hot conditions.

Anyone heard of them stretching? The chains are quite long so I suspect it would only take a small percentage increase to give me my problem.

If they do - are they a B'stard to replace?

i think i may have the same do you get a knock on start up then goes quite when warm but on exceleration get a camy chain rattle at about 3/4 thousand revs and a not so noisy cam chain knock noise on deleration my seems to be left hand side i,ve changed everything and its still there and i get iratic idle i do also get a chain noise on idle .would be grateful for any updates you get on this issue

 

[monkeyboy]

i think i may have the same do you get a knock on start up then goes quite when warm but on exceleration get a camy chain rattle at about 3/4 thousand revs and a not so noisy cam chain knock noise on deleration my seems to be left hand side i,ve changed everything and its still there and i get iratic idle i do also get a chain noise on idle .would be grateful for any updates you get on this issue

What have you changed? It might be useful to know in my investigations. Mine is quite quiet when cold but when hot on idle it sounds very broken. I do get nasty chainy noises on overrun too. Its the fact that it seems to be destroying tensioners that leads me towards a very loose chain being the problem - nothing else. I read elsewhere about these noises not being a problem but I've done 250k on these and this is definitely a 'fix me or else' noise. It is getting worse quite quickly too which I just don't understand. Maybe it could be something to do with oil pressure but I've just changed it and it made no difference. I'm currently stumped. As I have the head off I might as well change the chain bit it looks an absolute bitch job. The chains are continuous, not linked for a start though there may be linked replacements available hopefully!

 

[chad]

wasnt the 1150 subject to an upgrade on the cam chain tentioners yours may never have been done , might be worth doing these first

 

[ChrisH Kerry]

wasnt the 1150 subject to an upgrade on the cam chain tentioners yours may never have been done , might be worth doing these first

Think he's done that:

It sounds very 'cam chainy' so I initially got a new tensioner........

.......I re-fitted the old style original one

Cam chains do stretch so that may be your problem on high mileage engine, especially if it's been flapping around for a while. Are you certain that the guide bars aren't broken? That was the problem with another bike here - might be worth a read.
There shouldn't be any movement in the cam if the chain is tensioned properly AFAIK.

 

[monkeyboy]

Yep, the original tensioner has been replaced with the upgraded piston type and it has twice buggered the piston by making it lock solid, I think due to over extension.

I have checked the guides and they are in one piece and undamaged as far as I can see without taking the actual cylinder off. I'll take another look though. I've got an old r1100s engine that's partially dismantled for reference and the guides look the same.

I'll speak to motor works and see what the options are regards chains. Looks like changing one could be hard and getting the timing right would be a worry but not impossible clearly.

 

[monkeyboy]

Think he's done that:





Cam chains do stretch so that may be your problem on high mileage engine, especially if it's been flapping around for a while. Are you certain that the guide bars aren't broken? That was the problem with another bike here - might be worth a read.
There shouldn't be any movement in the cam if the chain is tensioned properly AFAIK.

Just checked the video of the broken guide noise. Mine is nothing like that. Its not constant and is definitely a chainy noise rather than flappy.

 

[taffyflytyer]

Just checked the video of the broken guide noise. Mine is nothing like that. Its not constant and is definitely a chainy noise rather than flappy.

mine the same not constant if i go for a long ride it gets a bit quiter as if the metal has expanded and closed a gap somewhere but its still there its hard to hear if on tick over but when you ride it you can hear it on exceleration and deceleration driving me nuts

 

[Kenny Rodkiss]

Yep, the original tensioner has been replaced with the upgraded piston type and it has twice buggered the piston by making it lock solid, I think due to over extension.

The tensioner piston has a spring loaded one way ball valve that allows oil into the piston but not out.
It is supposed to do this to maintain chain tension.
It is oil pressure that tensions the cam chains.
the old style tensioner had a groove down the side that let the oil out and left the tensioner slack until there was sufficient oil pressure to to keep the tensioner under pressure.

 

[monkeyboy]

The tensioner piston has a spring loaded one way ball valve that allows oil into the piston but not out.
It is supposed to do this to maintain chain tension.
It is oil pressure that tensions the cam chains.
the old style tensioner had a groove down the side that let the oil out and left the tensioner slack until there was sufficient oil pressure to to keep the tensioner under pressure.

OK, thanks. So I have a new style cam chain tensioner in my hand that I cannot compress and that is locked solid. I assume what you are telling me is they pump up and stay pumped up, even after the engine is turned off and the piston removed? That's how they should be? I assumed they would decompress when the engine stopped. So if I fit a new chain, this locked piston is going to be too long for the new tension.

Any road up, its rattling like a bitch so I'm guessing the chain is so slack that even a fully extended piston can't take up the slack.

 

[Timolgra]

OK, thanks. So I have a new style cam chain tensioner in my hand that I cannot compress and that is locked solid. I assume what you are telling me is they pump up and stay pumped up, even after the engine is turned off and the piston removed? That's how they should be? I assumed they would decompress when the engine stopped. So if I fit a new chain, this locked piston is going to be too long for the new tension.

The oil causes it to appear locked up,

 

[Captain Black]

Has the bike done 250,000 ,miles ?

 

[monkeyboy]

Has the bike done 250,000 ,miles ?

Only done 100k

As for appearing locked up, must be a perfect seal in there as it's been out for two weeks and still won't move.

Either way, it still couldn't stop the chain flapping so it's going to be replaced.

 

[Kenny Rodkiss]

Think you can depress the ball valve to let the oil out.
You must have some other problem if it is still making a noise.
You have three chains mind,

 

[Timolgra]

As for appearing locked up, must be a perfect seal in there as it's been out for two weeks and still won't move.

Think you can depress the ball valve to let the oil out.