YZ426F Knock after hotcam install

3 replies to this topic
  • brian1000buddy

Posted January 06, 2012 - 04:44 PM


I just installed a hotcam auto decompression cam in my dirt bike. It starts first or second kick everytime. I can even start it with my hand now. However, it sounds like it is knocking now at all rpms. I checked the valve clearances and they look good. It did not knock before I put the hot cam in it and was wondering if anyone had any ideas before the dealership gets it.

  • sid_125_04

Posted January 06, 2012 - 07:06 PM


Check your timming and double check it. Mine sounded weird at first also and i did a 4hour break in, just putting around and then it quit sounding weird.....check it and be easy

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  • brian1000buddy

Posted January 06, 2012 - 07:23 PM


I am going to check the timing in the morning again and if it looks good ill take it to the dealer and see what they think it is

  • bonehead7101

Posted January 06, 2012 - 11:25 PM


Knocking or ticking. I have noticed ticking before from auto decomposition cams. Also did you torque the cam caps to the manual specs. They are very delicate and can easily get torn up if not torqued properly. And be sure the cam chain tensioner came out all the way I've had them stick in just enough that when the motor started running there was just a bit of chain slack.

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