I put in a wiseco high compression piston (13.9:1) in my 2010 RMZ 250.

I was involved in a first corner pile-up in my last race and found myself kicking the bike over for what felt like forever, it just wouldnt start!  It started much easier with the stock piston.

I kicked probably about 20 times with the hot start lever engaged, my valves were also just adjusted to spec before this race... anybody else with this piston notice it's harder to start the bike when its hot?

what octane of fuel are you running? if you are running a too low of an octane it will be hard to start when warm.

I'm running premium gas at the pump which is 91 octane

i have a 10 rmz 250 with a 269kit in it with high comp and anytime i stall or shut it off i have to pull the choke (fast idle) knob out. it will not start with the hot start lever pulled ever. i have tried all the plugs and the rich plug works the best. hope this helps!

I never tried using the choke for hot starts... I'll have to try this out next time, thanks!