Back in the late 90's there was a guy in my complex Sandy Rainey.. He built Yamaha two stroke engines for GP Motorcycle racing... He would alter the port timing by adding epoxy to the transfer ports & exhaust port.... In a two stroke there are no valves, the piston opens & closes the ports, that means the rings are in contact with the epoxy... Sandy tried a lot of different epoxies & no normal products could survive at 16,000 rpms & exhaust temp pushing 950 degrees... He only found one product that lived in that environment & it came from Japan... It wasn't available in the US.. Whenever he travelled to Japan he would bring a few boxes of it back with him...
Oh, his son was a pretty talented rider... Wayne Rainey... Three Time GP Motorcycle World Champion
https://global.yamaha-motor.com/race/wgp-50th/race_archive/riders/wayne_rainey/