Trying to identify a new noise... (maybe the clutch, or gearbox?)
05-23-2007, 09:52 AM
#1
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Squid
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Join Date: Jan 2007
Posts: 26
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.
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.
05-23-2007, 10:43 AM
#6
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Squid
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Join Date: Jan 2007
Posts: 26
I can rev the engine in neutral with no noise, same with the clutch fully pulled in.
05-23-2007, 10:49 AM
#7
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Squid
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Join Date: Jan 2007
Posts: 26
I figure anything else I put there, tape, wax, or something would just melt off...
05-23-2007, 11:30 AM
#9
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SuperSport
Join Date: May 2005
Location: North Wales, PA
Posts: 809
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.
05-23-2007, 12:22 PM
#11
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Back Marker
Join Date: Oct 2006
Location: New England
Posts: 230
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.
05-23-2007, 01:09 PM
#13
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Superstock
Join Date: Dec 2005
Posts: 428
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.
05-23-2007, 05:10 PM
#14
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MotoGP
Join Date: Sep 2006
Location: Austin, Tx
Posts: 4,138
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.
05-23-2007, 05:37 PM
#15
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Squid
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Join Date: Jan 2007
Posts: 26
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
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
05-23-2007, 08:22 PM
#16
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World Champion
Join Date: Dec 2004
Location: Fulton, MO
Posts: 105,287
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.
05-24-2007, 06:23 AM
#17
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Squid
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Join Date: Jan 2007
Posts: 26
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.
Thanks again.
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