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Did you set the squish before doing the head? I've heard it's one of the first things you should do to these yz's because it's pretty loose from the factory.

Finally, went with the Acerbis number plate, all OK. I think that the YZF fender and plate are more in line with the current YZ design.

The 2003 to 2010 USA model head will have more compression than all the others. You are better off sending a head to a good engine builder to have it machined for tighter clearance. If you run race fuel, you can bump the compression a bit beyond the 2003 - 2010 USA spec. I start with the 1999 - 2002 heads and machine them to my own spec.

I'm thinking it's more likely a combination of port, PV and ignition timing - it seems like I remember the dip on most HP plots occurred at the PV opening and then regained the positive slope as the pipe and ignition advance came into tune with the now larger exhaust port area. The bike builds I've seen that address similar situations are usually looking at those areas. An electronic PV (like the last CRs) would allow more tunabilty/synchronization with the others versus a mechanical PV controlled by spring tension that opens over a narrow RPM range. I'd like to see...

Accomplished my goal of getting into the top 10 overall for all A riders in district 36 cross country last year and as a participation award get to run the red plates for a year. Bike only looks the shiny one time! Back to Racing this Sunday, but definitely not doing the full season this year.

@crujones7 after this it’s definitely time for a 300 kit!

I will Take it, sent you a PM

Been on a 2012 Honda Crf250r since 2013. Excited to build this thing up. Bought at a good time of year to get it setup, but a bad time because gotta stare at it in the garage till it warms up here in Indiana. But man it’s beautiful machine…