RE: Welcome to Club SAITO !
This cylinder is from a 1991 HighCompression 1.50, as you can see the only black is around the exhaust valve. This eniges was run for two seasons on Fox 15%/20% castor. (before I knew better). I replaced the cylinder pictured because I broke it ham fisting the intake nut. I think a testament for WildCat fuel is in order, I re-used the original piston and ring and it still has the original bearings in it. I have an .80 the same age, maybe one year newer still all original. The fuel I use almost exclusively is WildCat 10 or 15% with 18% 80/20 syn/castor blend. Last season I used 6 gallons of PM of the same formula.