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I sure did! There is a sharp ridge in the combustion chamber that leads to 'hotspots.'

 

Technically the difference between the WR500 and the YZ490 motor is that they lowered the compression and got rid of the detonation issues. I also performed the "ridge removal" to guarantee success.

 

I tried to overheat this bike a few times to get it to detonate... Never happened. She just runs better and better and better the hotter she gets. Jetting is SPOT ON. -BIG DAN:thumb:


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