Noisey heads

monkeyboy

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OK - I know this may have been covered a bizillion times, and that any 'what's this noise' thing is very subjective and almost impossible to diagnose like this but.... I'd like a little advise just to get my head out of this endless loop it's got itself in. I'm taking the bike on a long journey and I'm running out of time to either sort it out or to convince myself that it will all be alright.

The basic problem is that the left head is very very noisy at particular revs. It sounds like there are a hundred little blacksmiths in there some of the time, banging away with their little hammers.

I've done quite a bit with this head/cylinder over the last year so it's probably my fault:) I originally changed the tensioner to the new style one - not much difference, though the new tensioner quickly seized open - I took it out to check and it would not compress without putting it in a vice! OK I thought - max tension all the time - can't be bad...

Still noisy - so I changed the cam chains. Did both sides as the bike had done about 100k anyway. A lot better.

Later I had to take the exhaust off - age old problem, the bolts sheared. Took the head off - tried to drill them out. Snapped a drill bit so had them spark eroded but this resulted in a hole appearing effectively into the chamber so I had to chuck it away. I had an R1100S head kicking about so I de-coked it and reground the valves then put the R1150GS valve gear in - I think it's only the cam that different R1150GS/1100S.

So it's all been back together for a while and running - it's done about 107k now - but the left head is SOOOOOO noisy around 3.5 to 4.5. It all sounds very 'tinkly' and loose. I've checked/adjusted the valves and rechecked but still really noisy. I've also replaced the seized tensioner but still not much better.

If anyone has any idea about things that I could check/think about I would appreciate it. It's nice an quite (ie normal) at other revs, just particular ranges seem to set it off. I've got loads of bits at home I could swap - though they're all 1100S so not the cam. Could it be the followers? Could I just tighten the valves a tad (excactly how much is a tad anyway!) or should I just have my ears removed and forget about it.
 
I would have thought that a slack valve clearance would rattle throughout the rev range, not just at certain revs. I wouldn't advise tightening the clearances as the risk of burning a valve would be increased. I do wonder if the noise could be a loose end on one or other of the pushrods? Another possibility could be the end-float on the rocker shaft is too big. A grown-up will probably be along soon with better advice......
 
I've checked the float - that seems OK. I've had big ends and little ends go on cars and they make a different (lower) frequency noise than this (hopefully!) as they're moving more slowly so hopefully not that. As misplaced or missing collet on the valve - I hadn't thought of that. They can't be loose cos they'd just come out. I'll have a look at check. Someone just suggested to me that the teeth on the cam sprocket could be worn which I'd not thought about but I've never heard of that happening before in this situation. I'll pop a different cam sprocket on at the weekend and see if that changes it too. I'll try anything!
 
Just to be clear, it wasn't the valve collets I was meaning, rather the pushrods that fit into the lifters (in BMW speak). These have end pieces that can come loose, causing a rattle. There is a thread somewhere on this forum about the subject. Can't really see cam sprocket wear as the issue, though I suppose at high mileage anything is possible. Good luck anyway.
 
I'm not sure I understand that TBH. 'end pieces'? The valves (pushrods) are solid. There is just the spring and the round detent held in by the collets. The cam follower is a single piece then there is the cam. If you can remember anything about the other thread then that would be good:) Thanks anyway
 
Just to be clear, it wasn't the valve collets I was meaning, rather the pushrods that fit into the lifters (in BMW speak). These have end pieces that can come loose, causing a rattle. There is a thread somewhere on this forum about the subject.

I posted it a few years ago. The end balls can make a noise. They feel fine when cold, but work loose as the engine heats up.

Old


The new type
[/QUOTE]
 
Ahhhhhhhhhhhhh. Blimey - that looks like a likely candidate then - thanks. I'd completely forgotten about those. They'll be the old kind definitely. I can replace those no probs. Time to use the BatPhone (Motoworks) and contribute to the Yorkshire economy..... again.

FYI - in case anyone else searches for this in the future, the part number for the upgrade is 11317688631 (valve pushrod) and you can only buy them through BMW direct - £20 a piece.
 


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