firstly as said, the blocked fuel cap vent a favourite especially on bikes used on dirt.
secondly, Its a problem I worry about, Ive rebuilt a customers DR400 engine, the frame is still not ready for the motor thats nearly a year on the floor, no lubrication going around the bearings although I have used plenty of oil in the rebuild. the latest B40 motor rebuilt a year ago and not near starting yet, but I have tried to keep it turning.
I had a can-am bombardier that nipped up on a long ride , waited until it cooled down and it ran again enough to get me where I was going and back home,
maybe a clearance issue, something may have closed up due to heat