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Noise on startup when cold (overnight) is the most common. I guess in certain cases over time it beats the chain guide to the point of breaking. Left side is the one that makes the noise. It is on top behind the throttle. Parts are about $130 right now. I have replaced mine. There is no more noise (mine was a little noisy on startup before)
Parts are less than $90 from Rubber Chicken Racing.
I have a 04 1150 GSA with 25k Should I be concerned about this cam chain tensioner thing? What are the symptoms?
If you wear ear plugs, you might not hear the noise. Also, if you start up cold and ride away you may not ever hear the sound.
To truely test for the sound you need a helper to start the bike. A rally or tech day would be a good place to have someone check. With your millage it is unlikely you need to do anything. Normally, only high millage bikes have issues with cam chain tensioners. To test for a cam chain tensioner failure you or your helper has to listen for the sound on the cyclinder head after the bike is warmed up. The flapping happens when oil pressure has not built up to the nominal rate. So, it is probably from 0-30 seconds after the bike is started. After that the flapping will go away and the bike should sound like a sewing machine. You will have to let the bike sit for at least 10-30 seconds for the oil pressure to drop back to zero after turning it off. You need to listen to both cyclinder heads, but the left side seems to fail more than the right for some reason it seems.
Also, according to Chris Harris of 'affordable BMW repair' in NH cam chain tensioners don't fail until about 80K.
I had 83K on my bike when mine failed.
I'm gonna go out on a limb here and say that if the chain skips just one link, much less fail totally, it'll cost way more than $90.
You may already have the new style - check the head size.
Don't wait
There are those that believe that the old style tensioners contribute to the chain guides breaking and that is real bad news. Replace if you have the old style.
Head size? What do you mean exactly.
Original part has 17mm head size, updated one has 15mm head size (top the the tensioner hex)
Head size? What do you mean exactly.
Don't wait
There are those that believe that the old style tensioners contribute to the chain guides breaking and that is real bad news. Replace if you have the old style.
The LHS cam chain is being improperly tensioned with original tensioner, it's just a question of how long one can get away with it.
That said, OP can probably wait till 50k maintenance.
My LHS tensioner failed at about 130k miles. The plastic chain guides had been worn through, then shattered, then the chain jumped off the sprocket and kinked.
Some speculation on causes, perhaps real experts will comment:
-the old LHS tensioner (17mm bolt head, 1998-2006?) failed due to clogged oil port, causing the piston to stick instead of pushing down on the upper chain guide.
-the RHS tensioner never (?) fails, because its piston pushes UP and somehow the oil drains from it without problem.
-it's possible that frequent oil changes help prolong the original LHS tensioner, which depends on very clean oil.
..I have read that the Left one drains down on a hot shut off. When the bike is started the next time there is little tension until the oil pressure builds.
The Right one does not drain down because it is inverted under the cylinder.
That makes much more sense, thanks.