I like the higher compression piston in most cases. That YFZ has a serious pancake piston. There is virtually no skirt at all. The thing that will kill you on a pancake piston is any detonation at all. Don't chince on octane.

Tony this will be a good experience to see what the motor looks like after 180 hrs of ride time after our trip. Your riding style is very consistent and if everything looks quite good, no ridge or anything, I would put a higher compression piston in and get a valve job with new springs, re-hone the cylinder and put her back together. I would then go longer than 150 hours next time since everything seemed to lok ok.

I would not just close it up once you have it open.

If it looks pretty worn out, you may need to bore your cylinder a touch and re coat it, I would then check it again at 150 hrs or a little before.

Te best thing about the 13:1 compression is how much quicker the motor will spin up. You will find gains from bottom to top.

 

Actually, KBR sells the 12.25:1 piston that you can run on pump gas. Now thats nice. [img]i/expressions/face-icon-small-wink.gif[/img]