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Engine noise YFM350

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  #11  
Old 11-01-2006, 03:38 PM
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Default Engine noise YFM350

sounds very similar to my buddie's warrior .. just before it went "pop" and died.

He had his fixed once before and it was a bolt or nut loose within the head. His ticking was worse though, and didn't die off under varying throttle conditions .. it just increased or decreased with the engine speed.
 
  #12  
Old 11-01-2006, 10:40 PM
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Default Engine noise YFM350

Originally posted by: NorthernATVer
Balancer drive gear.... interesting. Are you thinking that there is a problem with it or just that some are noisy?


Well i think some are noisy and higher the millage louder the noise.

Remember this balancer drive gear thing is only theoretical.

p.s: Sorry for my not so perfect english !
 
  #13  
Old 11-10-2006, 04:21 PM
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Default Engine noise YFM350

Check , 1, the Crankshaft main bearing, 2, the connecting rod bearing, 3 piston pinn slack
 
  #14  
Old 11-11-2006, 08:18 AM
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Default Engine noise YFM350

Nekro.... did you read the complete thread?
 
  #15  
Old 11-13-2006, 10:03 AM
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Default Engine noise YFM350

Yeah, but none of all your tips have help speedoo ...
 
  #16  
Old 11-13-2006, 12:23 PM
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Default Engine noise YFM350

Originally posted by: Speeddoo
Definitely not piston slap nor the top end, does'nt knock under load so we can rule out the crank. I've analyse the noise with an audio editing program and was able to determine the frequency of the noise, it knocks on the power stroke (every 2 revolutions).

NorthernATVer is right its hard to tell where it is coming from, i've tried several time with an electronic sthetoscope and was unable to pin point the noise.

I'll keep you posted if i find anything. [img]i/expressions/face-icon-small-wink.gif[/img]

-Speeddoo-
The above is what I was referring to.

My brand new machine made and still makes the same noise. I pounded the heck out of it when it was under warranty hoping it would break. It didn't. Hard for me to believe its the main bearing, connecting rod bearing or the piston pin.

Maybe I'm wrong and someday I'll eat my words, but I was trying to help Speeddoo with what I feel is a very elusive noise that may be normal (or at least not self destructive) in some YFM 350s.

 
  #17  
Old 11-14-2006, 10:50 AM
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Default Engine noise YFM350

thank, i am very happy to know that your new machine do the same noise, i just buy a 1989 bigbear 350 that do the same noise, then i about to tear it dowm to point the problem, so, i keep if i can found anything, i will tell you !
 
  #18  
Old 11-30-2006, 11:13 AM
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Default Engine noise YFM350

Hi, i have tear down the my engine, and found the problem, it in the camshaft in the engine head, The problem is that the inner camshaft roller bearing was completely destroy, i had to repair the head and change the camshaft. Now the engine noise was a lot better, and my moter acceleration is much better.

 
  #19  
Old 03-09-2007, 09:05 AM
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Default Engine noise YFM350

bump... to keep this thread alive. I'm sure there are more YFM 350s with this type of noise out there!
 
  #20  
Old 03-09-2007, 11:38 PM
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Default Engine noise YFM350

Well guys that engine got me puzzled, the noise didn't happen when the engine was cold so i had ruled out piston slap. (piston slap is greater when the engine is cold and diminished when hot, piston expand)
Had the atv last month for a re-ring, had to send the cylinder for boring and put in a new piston and ring put everything together and guess what no more noise!! [img]i/expressions/face-icon-small-confused.gif[/img]
 


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