Yz144 won't start when hot?

[speedtoad]

I have a 2005 yz125 with an Athena big bore I installed last summer. It run good. Spark plug looks good. Its not running rich.

After riding it hard and its stink'n hot it won't start until it cools down. It will bump start when hot.

Any ideas.

[twostroke-notbroke]

Clean the carb and check the compression

[speedtoad]

2 hours ago, twostroke-notbroke said:

Clean the carb and check the compression

Compression is 165 psi and carb is clean.  idles and runs great.

[claymoto471]

my rm125 had this problem one day at the track. couldnt kick start it after the first moto. had to bump start it and it would run ok. turned out it was my top end. replaced the top end and it fixed it. but it could be more. just an idea. pull it apart and check

[speedtoad]

Was thinking maybe it was vapor locking?
Rode it pretty hard today. I am going to check clutch tomorrow and see if its slipping and heating up.