Clunk noise
#1
06-17-2007, 10:29 PM
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Clunk noise
2003 400fis auto.
I picked up a noise yesterday. I can't notice it riding (it may be there), but while in neutral when it rev's up and comes back toward idle there is a 'clunk'. Not only audible but you can feel it in the foot pegs. Seems to be coming from the clutch/belt side. Similar to what a bad universal sounds like in a car. Was wondering if the clutches are engaging and disengaging or something.
Anyone got any ideas? or had the same 'clunk' sound and found the source?
I picked up a noise yesterday. I can't notice it riding (it may be there), but while in neutral when it rev's up and comes back toward idle there is a 'clunk'. Not only audible but you can feel it in the foot pegs. Seems to be coming from the clutch/belt side. Similar to what a bad universal sounds like in a car. Was wondering if the clutches are engaging and disengaging or something.
Anyone got any ideas? or had the same 'clunk' sound and found the source?
#2
06-19-2007, 04:56 PM
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Clunk noise
Buckaroo,
Don't rev it up in neutral and you won't hear or feel the clunk!
Ok, that was the not so smart answer not for, um, another answer. I wonder if you could be feeling the springs disengage when the RPM's get low enough? OR you may be hearing the compression release valve?
My wife's TRV with the 500 auto in it does not make that kind of noise. You can remove the belt cover and inspect the clutch. All I hear is a high pitched whinning noise when its revved up in neutral.
SJ
Don't rev it up in neutral and you won't hear or feel the clunk!
Ok, that was the not so smart answer not for, um, another answer. I wonder if you could be feeling the springs disengage when the RPM's get low enough? OR you may be hearing the compression release valve?
My wife's TRV with the 500 auto in it does not make that kind of noise. You can remove the belt cover and inspect the clutch. All I hear is a high pitched whinning noise when its revved up in neutral.
SJ
#3
06-19-2007, 06:57 PM
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Clunk noise
I don't believe my 400 has a compression release valve. That 'clunk' has me stumped for sure. Only other thing that I have ever done was the other day I started it with the pull cord which I have never done. I just did it to see if I could... since then there is a clunk so maybe the pull cord didn't reseat properly,, who knows? It still sounds like the clutch area. I have notice lately that on occasion it shifts hard - on the selector lever. (going from reverse to neutral, to drive, low-range, and back. This week if I get a chance I will pull the side cover and have a 'look-see'.
#5
06-19-2007, 09:19 PM
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Clunk noise
<div class="FTQUOTE"><begin quote>Originally posted by: v2rider
Mine does the exact same thing. My dealer said it was normal, about 700 miles ago and no trouble. He said its the clutch engaging/disengaging</end quote></div>
Thanks 'V2', that is what I kind of thought but I have 2600 miles on it and I just noticed it lately, probably within the last 100 miles or so.
Got a question for you guys... I noticed that my pilot jet was turned out 3+ turns and the manual calls for 1 1/8 turns so I kind of split the difference and am at about 2 turns out. I did some 'air-jetting' to get more air to my air box and now on decelleration down long hills, on occasion it will 'backfire' (that is a first too - lol), now is that meaning a lean condition or rich. I think lean but I can also remember turning off the ignition on a car and then turning it back on and getting a 'backfire'.. unburned gas in the exhaust - rich condition... What do you guys think?
Mine does the exact same thing. My dealer said it was normal, about 700 miles ago and no trouble. He said its the clutch engaging/disengaging</end quote></div>
Thanks 'V2', that is what I kind of thought but I have 2600 miles on it and I just noticed it lately, probably within the last 100 miles or so.
Got a question for you guys... I noticed that my pilot jet was turned out 3+ turns and the manual calls for 1 1/8 turns so I kind of split the difference and am at about 2 turns out. I did some 'air-jetting' to get more air to my air box and now on decelleration down long hills, on occasion it will 'backfire' (that is a first too - lol), now is that meaning a lean condition or rich. I think lean but I can also remember turning off the ignition on a car and then turning it back on and getting a 'backfire'.. unburned gas in the exhaust - rich condition... What do you guys think?
#6
06-19-2007, 09:28 PM
Clunk noise
Im almost positive its a lean pop, but only significant if it happens constantly. But on the otherhand, the unburned fuel is true also. Mine does it upon slowing down also sometimes, but not if i swith from my K&N to the UNI. So that tells me its a hair to lean, but not enough to hurt anything.
#7
06-19-2007, 09:39 PM
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Maybe I will try turning my pilot screw in a tad and see. Darn pilot screw adjustment, I have to loosen the carb from the manifolds and turn it on its side to get a small screwdriver in there. I saw a pilot screw with a built on screwdriver (but that was for a mikuni and my carb is a keihin). Maybe I can take the pilot screw out and solder a small screwdriver to it - (I can take a roofing nail and flatten the tip and grind it to the shape of a screwdriver)... lol....
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#8
06-20-2007, 10:12 PM
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Clunk noise
Found an interesting article:
4: Backfires in Exhaust
Note:
It is normal for many high performance exhaust systems to moderately backfire or pop when the throttle is closed from mid-to-high rpm. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm.
The popping is a result of the air/fuel mixture becoming very lean when the throttle is closed and the engine is rotating well above idle speed. It is also necessary that the exhaust system have rather open mufflers.
Why This (normally) Happens:
1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ---- the exhaust then pops or backfires.
4: Backfires in Exhaust
Note:
It is normal for many high performance exhaust systems to moderately backfire or pop when the throttle is closed from mid-to-high rpm. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm.
The popping is a result of the air/fuel mixture becoming very lean when the throttle is closed and the engine is rotating well above idle speed. It is also necessary that the exhaust system have rather open mufflers.
Why This (normally) Happens:
1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ---- the exhaust then pops or backfires.
#9
06-20-2007, 10:33 PM
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Clunk noise
<div class="FTQUOTE"><begin quote>Originally posted by: swampyjunior
Buckaroo,
Don't rev it up in neutral and you won't hear or feel the clunk!
SJ</end quote></div>
I knew that, I suppose I could always wear 'ear-plugs' and lift my feet off the foot-rest. lol
Swampy where have you been the past couple weeks, laying low - the 'law' looking for you? hehehe
Buckaroo,
Don't rev it up in neutral and you won't hear or feel the clunk!
SJ</end quote></div>
I knew that, I suppose I could always wear 'ear-plugs' and lift my feet off the foot-rest. lol
Swampy where have you been the past couple weeks, laying low - the 'law' looking for you? hehehe
#10
06-21-2007, 03:59 PM
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Clunk noise
Buckaroo,
Naw as far as I know the law is not looking for me...yet.
I was bear hunting for a week. Dodging the brownies looking for something black. Finally, on the 4th day I got about a 6ft 250lb black bear. Not big but, it will do. After coming home and caring for that I got a call from a friend who said the King salmon are in and off I went with my fishing pole in hand fishing.
You might say I am home recovering or recooperating. I have 5 really nice 25-38lb kings in the freezer along with a couple of sockeye salmon and I am looking to add some more halibut and sockeye salmon before things get crowded.
Then I will lay low until moose season the end of August.
To keep from feeling the clunk you might try a good set of gel insoles in your boots (are you gellin'?) and a cheap set of ear plugs from walmart. Or if you removed your foot rests then....
SJ
Naw as far as I know the law is not looking for me...yet.
I was bear hunting for a week. Dodging the brownies looking for something black. Finally, on the 4th day I got about a 6ft 250lb black bear. Not big but, it will do. After coming home and caring for that I got a call from a friend who said the King salmon are in and off I went with my fishing pole in hand fishing.
You might say I am home recovering or recooperating. I have 5 really nice 25-38lb kings in the freezer along with a couple of sockeye salmon and I am looking to add some more halibut and sockeye salmon before things get crowded.
Then I will lay low until moose season the end of August.
To keep from feeling the clunk you might try a good set of gel insoles in your boots (are you gellin'?) and a cheap set of ear plugs from walmart. Or if you removed your foot rests then....
SJ