2009 YZ450F piston knocking?


10 replies to this topic
  • 307luke

Posted July 16, 2010 - 06:39 AM

#1

I have had the 2009 YZ450F for about 1 year and have put maybe 25 hours on it. I have not raced the bike or even rode it extremely hard. I change the oil and clean the air filter after every other ride. Just this spring I noticed a hollow sound coming from the motor when it is is idle or low rev. It almost sounds like I can hear a gentle knock in there and I am wondering if anyone else has this problem or if they would know what it is???

  • mx4god

Posted July 16, 2010 - 06:40 AM

#2

It might be a loose timing/cam chain.

  • grayracer513

Posted July 16, 2010 - 07:49 AM

#3

The most likely, and largely normal, source of this noise would be the primary gears. If the noise changes when you pull the clutch lever in, or disappears under a load, that's probably what it is.

Piston slap increases with load in almost all cases.

  • stroker101

Posted July 19, 2010 - 02:39 AM

#4

my 09 YZ450F has 14hrs on it. and it too has the same "hallow" sound (at idle). but when i pull the clutch in, the sound is non existant. i'm thinking harmonic noises from the clutch plates and basket is the cause. i beleive my previous yamaha's did the same thing and i think it's normal.

the previous bikes have never had clutch failures or any other issues

  • grayracer513

Posted July 19, 2010 - 06:12 AM

#5

my 09 YZ450F has 14hrs on it. and it too has the same "hallow" sound (at idle). but when i pull the clutch in, the sound is non existant.

That's nothing to do with the piston. Read:

http://www.thumperta...282#post5362282

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • 307luke

Posted July 19, 2010 - 09:35 AM

#6

Thanks for all of the comments back concerning the noise. I sure am glad this is a normal sound, it just seemed like I didn't hear this noise right off of factory floor. After adding the skid-plate I could definately hear the nose alot clearer. I will continue to ride without putting too much worry on the sound. Thanks again

  • grayracer513

Posted July 19, 2010 - 10:39 AM

#7

After adding the skid-plate I could definately hear the nose alot clearer.

:smirk: :smirk:

  • tnat1

Posted July 19, 2010 - 12:36 PM

#8

Thanks for all of the comments back concerning the noise. I sure am glad this is a normal sound, it just seemed like I didn't hear this noise right off of factory floor. After adding the skid-plate I could definately hear the nose alot clearer. I will continue to ride without putting too much worry on the sound. Thanks again


WIth the skid plate added it sounds like they left some jap engineers in there with ball peen hammers! They all do it! Your fine!

  • dvn

Posted July 19, 2010 - 05:36 PM

#9

They are noisy. It took me a while to ignore the racket. I don't even notice it any more. Now I just focus on how much fun this bike is to ride!

  • stroker101

Posted July 19, 2010 - 10:01 PM

#10

That's nothing to do with the piston. Read:

http://www.thumperta...282#post5362282


yeah, i know the clutch (plates and basket) has nothing to do with the "piston", i never said it did.

i was merely stating that when the clutch lever is pulled in and the clutch is disengaged, the noise (hollow sound) isnt present.

thanks for the link you (grayracer) provided. it was educational. but i still think the clutch is the culprit of the noise

  • dutchman780

Posted July 21, 2010 - 01:24 PM

#11

I have an 06 yz450f that does that... I didnt know what it was at first, but i scared the crap out of me! and its pretty liud, but like original ad said you pull the clutch in, it stops pretty fast, or if i go any more than 1/4 throttle it disapears too. I thought i bought myself a lemon for a minute there untill i read this. thanks for the post!
:smirk:





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