E-start & High Comp Piston?

4 replies to this topic
  • jnybbad1l40

Posted June 08, 2007 - 11:29 AM


Anyone with a 13:1 piston have any issues turning the motor over with the e-start? Is the decompression system up to the task with the higher compression?

  • jnybbad1l40

Posted June 09, 2007 - 03:10 PM



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  • Mutu

Posted June 10, 2007 - 02:09 AM


Yep... ME!!!!

I got a JE high comp piston in my '05, it is 12.7:1 in the WR.
The '05 WR is 12.3:1 stock and '05 YZ 12.5:1 stock.

I have to first say that I got hotcams as well that I installed at the same time, and the e-start is not strong enough to turn the motor over quick enough to start it. It turns over really slow. :ride:

I don't know if it is the cams, but the decomp pin is the same length as stock, so I think it is the piston.

For the gains of the extra .5 CR, I would just stick to stock piston and keep the e-start. :thumbsup:

Mine kickstarts easily every time though.......

Thinking about changing pistons? I did mine at about 5,000kms (3100 miles) and the stock piston and rings were in really good shape. :)

  • jnybbad1l40

Posted June 12, 2007 - 09:24 AM


Thanks for the info!!

  • Mutu

Posted June 14, 2007 - 12:20 AM


Had a chat to hotcams and they say the decomp actuator pin needs to be a bit longer for the wr when using a high comp piston.

Seems like it is the cams that is the problem and not the piston. :thumbsup:

When I get my issue resolved (not in the near future...) I will let you know how I get on. :thumbsup:


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