HELP cr500r getting smoked

this aint right, quads cant touch me but a xr650r and yzf 426 (stock as far as i know) are woopin me I would like some expert advice on some engine mods i got fmf pipe, boysen super stock valves, 1 mm over piston w/sleeve, 91 gas with klotz oil (20:1)and octane boost. the xr says i am quick till 60mph then slower til 80 where i top out. I would like to get more top end power. my idea right now is to port a little to match the new liner to the cylinder casting, and maybe two base gaskets. The internals do look good after the rebuild, so i think its jetted good and mixture is ok. But i need more two stoke advice for what really needs to be done to beat these guys.

wow if 80 is all you are getting my little quads will wear that thing out.

you need to pull that cylinder off and have it ported by a profesionall and send the head off with it to have the chamber reshaped, or buy a cool head with a CUSTOM cut dome. what carb are you running?

A decent running CR500 should S-M-O-K-E a YZF426.

Like Quick said, you need some porting. I'd call K&T in Utah - they did my two smoke Honda and made it scream.