What size piston??

[esr250r86]

Hi, I currently have a trx450r and I race mx with it. I have all my suspension done for now and now I need motor. I want to ask and see what would be the best upgrade to my stock motor that does not involve boring the cylinder out. I am already planning on getting a stage 2 hotcam but dont know what type of piston to get. I want to get a high compression piston but dont know what size I should go that will keep the motor reliable and still be quick. Any suggestions on brands and sizes or other mods would be appreciated. I currently have a yosh. trc full system,uni filter and some carb. mods done. Thanks.

[Turboderf]

keep it stock piston & rings plan on doing a valve job that will cost you about 400 or so kibblewhite valve & spring kit good luck

[IMSROLL450R]

If you still have the stock piston upgrade to a 12:1 or something comparable from Venom. Ive heard nothing but good from them. Could also send them your head and get it ported and polished as well as new valves all at once.

[4bidden]

Can't go bigger (bore) if you want to stay legal anyways Michael!! ;)

I've got a decently built motor that is still plenty reliable. I've never had a problem with it (knock on wood) and it has a 14:1 piston, porting, and a cam.

If you don't mind spending money on race gas, go for a 13.5:1 CP race piston. If you want to stay pump gas, find a 12.25:1 Venom piston.