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Trying to identify a new noise... (maybe the clutch, or gearbox?)

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Old 05-23-2007 | 10:52 AM
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Trying to identify a new noise... (maybe the clutch, or gearbox?)

From a dead stop (redlight, stop sign, etc), I accelerate in 1st gear, between 2000RPM and 3000RPM I make the shift to 2nd gear.

Inside of 2000rpm and 3000rpm, before, and after I shift, I hear an irregular noise coming from straight down. It's either the clutch/transmission or the bottom of the engine I guess (crankcase?).

Its an irregular noise that happens as I accelerate, I don't hear it on deceleration. It sounds as though its inside the engine or gearbox/transmission.

there is no pattern to the noise, just an odd set of soft metal hitting metal noises. It only happens in the accleration I mentioned above. If I have to slow down, it doesn't happen when I speed up again.

There is no engine power loss.
No clutch slipping / gear slipping.
the bike is perfectly stable.
I tightened the chain last weekend, that didn't make any difference.

Everything seems fine except for this noise.

Anyone have any thoughts on what could be causing the noise?

Thanks.
Old 05-23-2007 | 10:54 AM
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Check chain tension... could be hitting exhaust under acceleration.. it happens to me every now and then...
Old 05-23-2007 | 10:55 AM
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Are you hearing it only when you pull in the clutch? Or can you hear it with out touching the lever?
Old 05-23-2007 | 10:55 AM
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Originally Posted by duran
I tightened the chain last weekend, that didn't make any difference.Thanks.
Doh.. never mind...
Old 05-23-2007 | 10:56 AM
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Originally Posted by Cleveland
Doh.. never mind...
Good job. Try a little reading next time
Old 05-23-2007 | 11:43 AM
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Originally Posted by drew_c14
Are you hearing it only when you pull in the clutch? Or can you hear it with out touching the lever?
I hear it with out touching the lever, its not when I pull in the clutch, its only at the tail end of clutch release (once things are back in gear) and when I'm completely off the clutch.

I can rev the engine in neutral with no noise, same with the clutch fully pulled in.
Old 05-23-2007 | 11:49 AM
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Originally Posted by Cleveland
Check chain tension... could be hitting exhaust under acceleration.. it happens to me every now and then...
I did that, as stated, but one thought I had was wrapping some aluminum foil where the chain could hit the pipe, and see if anything scrapes off...

I figure anything else I put there, tape, wax, or something would just melt off...
Old 05-23-2007 | 12:18 PM
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Originally Posted by drew_c14
Good job. Try a little reading next time
Old 05-23-2007 | 12:30 PM
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is it possible that you're hearing the carb slides clackin away. sounds like the right rpm. can you feel this sound in your feet through the pegs? or just hear it? is it a soft ticking sound? I'm guessing slides.
Old 05-23-2007 | 12:38 PM
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I don't feel it, I hear it.
I could describe it as a ticking noise, but it would be a LOUD ticking.

again, its not regular.
Old 05-23-2007 | 01:22 PM
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silly question.... does it happen when you drag the front brake? I had a noise like that when I had a dirty piston in the caliper. It wouldnt retract all the way. It was only right after leaving from a stop.
Old 05-23-2007 | 01:24 PM
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umm
good question, I'll try that this evening.

but I'm pretty sure its coming from below me, not in front of me.
Old 05-23-2007 | 02:09 PM
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Does it happen over and over again or just when its cold and you first take off? If it happens just when you first take off it might be the engine isn't quite up to operating temp and the valves tick because when they are cold they have greater clearance. Otherwise I might I would maybe think the timing chain gets a bit of slack during idle and then the first accel pulls the slack out. It is possible your tensioner is slowly backing off when sitting and/or idling.
Old 05-23-2007 | 06:10 PM
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I agree with Swordfish. I think it's the carb slides. It's sort of a chuckling, clacking, rattle kinda noise especially when you're digging out of a slow+/-tight turn. I don't feel it in my feet but I do hear it.
Old 05-23-2007 | 06:37 PM
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Something new.
Home from work, back the bike in to my spot at home, and as I let go of the clutch after putting it in to neutral, I hear the noise, but MUCH quieter.

As soon as I fully release the clutch, the noise stops, but if I pull it in ever so slightly, I hear it again.

Its not the louder version of the noise when I'm moving down the road, but its the same thing making the noise.

I'm going to have the bike in for the yearly inspection next month, so I'll hve them look at it for sure, but I want to make sure the thing isn't going to fall apart under me at 80mph

Any more thoughts?
The valve or carb idea is reassuring
Old 05-23-2007 | 09:22 PM
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You're hearing two different noises. The one under load at 2-3k is the carb slides. They're high enough that they come down to their stops on each cycle of the engine but not so high as to float above the stops. The other noise you hear at idle is the clutch plates. That's entirely normal too. A slightly thicker oil will quiet that one. Recommend 15w-50.
Old 05-24-2007 | 07:23 AM
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Originally Posted by Hawkrider
You're hearing two different noises. The one under load at 2-3k is the carb slides. They're high enough that they come down to their stops on each cycle of the engine but not so high as to float above the stops. The other noise you hear at idle is the clutch plates. That's entirely normal too. A slightly thicker oil will quiet that one. Recommend 15w-50.
The clutch plate makes sense in how I hear it, and when, but should the carb slides be irregular noises? Its not at all a pattern, or rhythmic in nature.

Thanks again.
Old 05-24-2007 | 11:26 PM
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Ah, not rythmic! Still might be the slides though. Could be the chain. I'd have to hear it to really identify it though. It's so difficult to troubleshoot noises over the internet.
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