2011 Issues - No start

1 reply to this topic
  • kjh440

Posted December 05, 2015 - 12:23 PM


I recently picked up 2011 YZ450. PO said it had bent exhaust vales.

I went through it and replaced the valves - just out of spec, with new OE valves.

Piston had no markings.

Shimmed everything to spec.

Put it together, started up just fine.

Took it out another time, started just fine.


Nice day today in MI, thought I would take it out.

No start. Kicked a long time. I know the starting routine as I also have a 2011.

Put in a fresh plug.

I got it started eventually by jumping it.

Shut it down and then tried to kick it again. No luck.


As I was kicking it,d several times the kick start seemed stuck, as though the decompression wasn't working. Rocked it in gear a bit, then able to kick again.


Wondering if I may have a bad cam that could be leading to decompression/no start issue?


Sorry for long post.


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  • grayracer513

Posted December 07, 2015 - 07:43 AM


If, when you kick it through at a moderate rate, there is what feels like normal cranking compression, then there's no issue with either the decomp system or the timing of the exhaust cam (says nothing about whether the intake might be off a tooth, though).


As far as the crank "sticking", bear in mind that the auto decompression setup takes itself out of play at about 650-700 RPM, and you can actually kick it faster than that if you try hard enough.  Could be what you're seeing there. 

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