i have a 92 250x with a 12:1 60. over wiseco piston. with 111 race gas mixed with 93 1/2 and 1/2. and a k/n filter ,cobra megaphone exhaust and i just had a velve job done i have 19" tires 13t and 36t sprockets i cant keep up with a bone stock 300ex i think it might be the jets. it was jeted just for pipe and filter. would i go up a jet size with the new piston and gas? it runs a little hot i think it takes a menit some times to idel down. i live in FL can someone please let me no were i should start what jets do you think i should have? i feel i wasted money

 

welp, what fuel are you using? is it oxygeneted? what size jets are in it now? what does the spark plug look like?

 

it has a 130 and a 35 i dont no what type of gas

 

i just tryed a 38 pilot the gas is sunoco racing fule 111. will the 12:1 piston and race gas make me need a smaller mane jet? it runs kinda good it just not fast like the 300ex the engine dont rap up fast i have to keep the rpm up hi to heep moving in sand and uses a lot of gas please help pro rider

 

have you looked at the spark plug to get a reading? it'll pretty much tell you if its running rich or lean. are you still running a stock cam? you could also try moving the clip on the needle down one notch. but i would do a plug check to see how its running first. just my two cents be nice to hear what more experenced ppl have to say.

 

well see my cam chane broke and tore up my cam so put a 300ex cam in it. so i hear its not as good as 250x cam. the plug is a dark brown

 

300ex cam is the same cam used in the 250x. to answer you other question with the t mark on the flywheel lined up with the mark in the inspection hole the two marks on the cam gear should be flush with the top of the head, with the middle mark pointing up. you could be off a tooth cause your lack of power, but imo you dont gain a whole lot of power just adding compresion,maybe alittle more bottom end grunt.