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Discussion Starter #1
Just completed a valve adjustment at 30K. Following Gunsmokes careful instructions to the letter. Reassembled and torqued everything up. Engine fired up but after running for 5 mins or so develops an intermittent and rather loud "chinking" knock. The noise seems to clear when the engine is revved. Carefully road tested the bike and without taking up above 3K (did not want to risk further!) it seems to be performing fine. Using the old screwdriver stethoscope trick the noise seems worst when held to the front exhaust manifold. The exhaust cam was left in place as only some of the intake valves were a little tight. The cam sprockets were lashed to the cam chain with cable ties to avoid an alteration in timing. Tonight have pulled the cam cover and can see nothing amiss. The noise only starts after the engine has warmed a little and is intermittent. I am stumped as to what the problem can be.

Any ideas/advice much appreciated.
 

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Assuming all is well on the top end, couldn't be a loose exhaust bolt or cracked exhuast flange?

Maybe record and youtube the noise.
 

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Discussion Starter #3
Cracked exhaust flange ?

Your suggestion might be right, i have been pondering that possibility, the front exhaust feels solidly in place when its cold, but the heat might expand and loosen it, maybe time to grab the oven gloves. The exhaust does sound different when the throttles blipped, sort of tinny rasp sound which was not there. Trouble is can i tell without pulling the whole system of and examining the flange.
 

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Will ride for picts
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Header leaks have caused several people to report strange noises from their engine. It's a cheap and easy thing to check, so I'd start there. If its not too bad, just tighten up the header nuts / studs and see if it goes away.
 

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Discussion Starter #5
Engine Noise Header Leak

Yep guys good advice , it looks like you were right, the front header bolts where not fully tight and there was carbon deposit around where the pipe seats into the head. Tightened it all up and just need to pop the cam cover back on and all should be fine.

If that's its a classic case of some completely unrelated problem cropping up at the same time ! Thanks for the advice
 

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Just another thought...remember that spring that is inside the valve cover?....did you put that back in place?
 

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Discussion Starter #7
All sounding sweet

Loose exhaust flange was the culprit......all sorted, thanks for the suggestion JCW
 

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Help

:dunno:

I believe I may have a similar issue, but mine has gone from annoying to scary :(

I also recently had the 24k valve inspection done by BMW, but this issue was present BEFORE the servicing... Although, is does seem a little WORSE since the servicing.

For quite some time my bike has made an intermittent 'rattling' noise while idling... Sometimes it would be only during warm-up, but other times even after bike had been running high RPM on freeway then stopping at a light, making noise at idle. Bike runs just fine at higher RPMs, issue is only noticeable around 1-1.5k RPM...

Also, while engine is 'rattling', idle RPM is erratic. It will fluctuate between 900-1.3k RPM erratically as if it is fighting to keep stable operation.

After reading above, I tightened all bolts mounting the headers to the case... They did tighten up a bit, but issue still exists.

I have uploaded a sound clip to YouTube of the symptom, pay close attention to engine after I rev it up to 2k RPM, when it falls back to idle it goes to shit. Gets terrible around the middle-end of the clip....

http://www.youtube.com/watch?v=K98XtnNP2v8
(Sound captured from clutch-side of engine, approx. 10in away from case.)

Please help. My baby sounds like she's dying :(
 

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My 2000 does the same thing. I assumed it was valve lash. I had the lash adjusted at the shop but when I got it back they said it was only out by the tiniest of margins and adjusting it did not get rid of the noise. They were unable to think of a cause but said they would begin researching the issue. That was 3 years ago. Subsequent visits to the shop revealed they have done some inquiries and have been keeping an ongoing log of customers complaining of the rattle. As of last summer no causes or cures have as yet been identified but almost half of all K-Bike sales out of that shop have had complaints of that issue after about 20,000 kms.
 

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ecapuano said:
I dont! But I've been contemplating it a while, perhaps I should look into that. It does sort of sound like the chain rattling, eh?
Second on it sounds like a chain slapping. I'd try the tensioner first (I changed mine out too). Then I'd look at that spacer thing with the oil pump (sprocket thickness change or some shimming if I recall?) if it still doesn't quiet down.

Might want to send the oil in for analysis and see if anything like odd plastic (i.e. nylon chain guide stuff) or metal shows up in it too.


Mack
 
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