wierd engine sound..piston slap?

3 replies to this topic
  • sprint4425

Posted October 08, 2007 - 07:17 PM


I have an '03 yz450. When i let the engine idle there is a slight knocking or slapping sound from my engine. Once i crack the throttle the noise seems to go away, but that might just because the exhaust is too loud to hear it.

Anyone have any idea's?

  • grayracer513

Posted October 08, 2007 - 08:42 PM




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  • 99raptor

Posted October 09, 2007 - 06:43 AM


If you have an alum. skid plate alot of noise is radiated upwards,making insignifigant noises seem scary.

  • tnl

Posted October 09, 2007 - 08:12 AM


Check your kickstarter lever (above part # 23: http://oem.thumperta...ickstarter.aspx ) to see if it's rattling from that location? Worth the check. Mine was making alot of noise from there and I thought that I had some issues with my engine before I caught it. If that's it, grease that fitting.

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