I've just bought a 2022 301RR. Previous owner did nothing with the bike, it's literally new. Bike starts ok cold, runs fine, idles, fan cuts in, but will not start when hot. I'm new to 4-strokes. I've filled it with fresh fuel, cleaned the air filter and replaced the spark plug, but get the same same issue. Can't find any loose plugs. Tried the ECU reset holding throttle open. Checked for throttle cable free play. Where should I start looking? Thanks

Adjust the valve clearance., it needs to be spot on and you just described the first symptom.

Agree with Lemur, most certainly the valve clearances. Get a workshop manual for the bike. There is a step by step walkthrough for everything. I’m sure there is also some advice on here. Not a hard job, but quite fiddly