My M20 is also new back on the road after a long lay-up, and suffering from reluctant starting from hot, so I don't offer it as a perfect role model. It would be interesting if anyone with a confident good runner could offer similar data. I got my IR thermometer as part of a tank sealant kit. There are identical ones on Ebay for £10.95 (black and yellow body).
On my M21 on a hot day(around 100F), I have measured the cylinder head temp at over 500F. The carb will boil over if you stop but the bike runs fine at these temps.
