Hicompression piston for 04 450EXC

[aussie_450exc]

Hey all, I just about to freshen up the top end on my 450exc and i want to put a hi compression piston in it but cannot find one besides the one in the hard equipment cataloge. They make hi comp pistons for the sx models as the run the bigger 95mm piston but the exc runs the 89mm piston. Has anyone found a hi comp piston for their exc. What brand and where??? Any help would be great!!?

[x2468]

what compression ratio is it stock? what about the new one?

[aussie_450exc]

The stock compression ratio for a 2004 450exc is 11:1 and i think the ktm hard equipment is 12:1 but i can't be certain. Have u found one from another piston manufacturer????

[x2468]

well im sure you could call wiseco or je and get them to make as high a comp one as you want for a price. but above 12 and you need race gas. im pretty sure

[Dave Hopkins]

KTM hard parts may have a high comps piston but I have used the Weisco high compression (beleive it is 12.5 to 1) with some minor head mods with excellent results. Stock the sides of the valves are too tight against the side of the combustion chamber to flow properly so I open this up with a radius cutter thus "unshrouding" the valve, this brings the compression ratio down slightly from 12.5 to 12.2 which works well with pump gas.

[Travis_D-37]

The KTM hard parts 450 89mm piston is made by Wiseco for KTM. Wiseco will not sell the piston direct you have to buy it through KTM hard parts

[Dave Hopkins]

Travis correct, I am thinking of the 95mm piston for 525.

Aussie, The way to get more power is either a 525 or a 540 conversion. The only time I would use compression over cubic inches to get more power is when you are competition class size limited

[Clark_Mason]

I installed a KTM hard parts Hi-compression piston in my 07 450 EXC and it added a very very slight thrust to the bottom end. I would not recommend using this piston as a performance increase unless you have other reasons to be working on the top end like new rings needed cracked piston but cylinder and head still serviceable etc., and for some reason you want to keep it a 450cc bike.

If you want more power go for the larger bore as stated above.

Cheers

Clark

[aussie_450exc]

Yeah i was gonna put a 540 kit on my bike 450but i think i might just buy a 525exc straight up beacuse my450exc has got a few hours u on it now so i might just freshen up the top end and sell it for a 525 a couple years newer. Thanks for all the avice anyways!!

Cheers fella's