2004 kx250f hot starting trouble

[campstove]

I just rebuilt the top end including complete new head, valves, springs, cams, chain, piston and rings. It runs awesome, but is a little hard starting when hot. I know this is an issue with these bikes. I need help with carb set up and tuning to see if it solves the issue. The carb is clean and in perfect shape. It does have the boyessen quick shot on it and the easy adjust air screw. Any info would be greatly appreciated. Thanks in advance!! I am to old to be kicking so much while my kids are riding.

 

[TheMuffinMan]

If you didn't cut the valve seats before putting in new valves then they may need some time to seat correctly. Right now you might not have a good valve seal which could cause your starting issues. Not cutting the seats will also mean that your valve clearances will tighten up very rapidly on break in so check them frequently during the first few hours of riding.