As mentioned , get your battery load tested first , if it tests good , then look at your starter , instead of explaining it to you , watch this video , a bad solenoid can cause this issue , could clean up the surfaces and see if that helps or just replace them . A worn out starter clutch would most likely be fussy no matter how hot / cold .

You can test your voltage at the single green wire on the starter , making sure your getting above 12v to it , then do a voltage drop test , shouldn't go below 10v , if it does , most likely a bad battery .

 

Releasing any compression that might be in the motor is only masking the real problem...your compensator is junk. Why would my motor do the same thing and it has acr's...wouldn't that blow a huge hole in your theory? I finally replaced the stock compensator with 70k on it and guess what it hasn't done since ??? Exactly...no hot start kick back. I knew it was bad but I didn't realize how bad until riding it the last few days.

 

did you buy the bike in 07 was it? and has it always had a hot start problem or is it new?

 

I bought the bike in July, 2019. It was a garage queen with 5000 miles when I got it. I first noticed the hot starting issue during the summer of 2020 when the bike had approximately 12k on the meter. The compensator has never clunked and neutral is easy to find. I have never checked the battery but the cables are clean and tight. The bike now has 28,500 miles and runs strong.

I ride it 30-50 miles daily but usually never have to hot start it. I just go for a ride and return home where it cools overnight. On the rare times I do hot start it it kicks back. That’s why I did the release of compression through the spark plug holes testing. Every time (5) after releasing the cylinder compression it started instantly without kickback with a fully heated motor.

After reading the comments I’m now thinking that the battery is probably a little too weak to crank through the heated compression but still strong enough to crank the motor without the added compression or when cold. But, I’m going to start by checking the battery.

The compensator is probably on its way too but just isn’t clunking yet. I do check the magnetic drain plug in Primary often watching for metal shavings. It always has a small amount of fine metal paste but no pieces/shavings.

 

You are probably right in suspecting the battery. No telling how old it was when you bought the bike two years ago. And many of the cheap Chi-Com batteries (and some of the more expensive brand names that come out of the same factory with a different label) only last a couple of years. A load test at your local battery store would be a good idea. A lot of modern batteries tend to fail catastrophically without much warning, leaving you standing in a parking lot miles from home with your d!ck in your hand.