13.1 je piston holding up in 2 hour xc race?

[Kilabanshee]

Well I'am about to install my 13.1 piston thermal coated so you can run on lower octane, along with getting my head ported and possibly a vortex ignition. Right now I have a sparks exhaust, hrc cam and k&n filter how much of a difference do you think ill notice with the new motor work? Do these pistons hold up in longer races such as a 2 hour xc race? I plan on doing the first d6 xc race I mix c-12 with sunoco 94 soo I wont be running any crap gas or oil I'm just wondering if it can take a 2 hour race without over heating ect. Currently I have my radiator fan off because of mx and track riding and really didnot have the need and it never seemed to kick on anyways, I was almost 100% intent on putting it back on but I just wanna get a few opinions.

[benwa450r]

I haven't experienced any more heat from 13:1 piston. I did go to 108 race gas. The alcohol in race fuel helps it run cooler. FYI.

[Kilabanshee]

Thanks, Yeah I was figuring it may have made more heat with the larger compression.

[1fast450R]

I have the Je 13:1 piston an I run vp c-12 fuel... I actually think the bike runs alot cooler, My pipe doesnt glow as much anymore... I am also running Engine Ice coolant, it helps alot...

[Kilabanshee]

Yeah ill have to give that a try can you get it at your local cycle shop, I'm gonna be getting some air scoops soon and along with the carbon fiber hood, I think that will be plenty of air to cool the motor and like you said it seems to be running around the same heat or alittle less if anything. What jetting do you sugest with this set up hrc cam, k&n, sparks exhaust, no air box lid, and the 13.1 piston and possibly a small self porting job?

[benwa450r]

I am running a 190 main, HRC needle on middle clip, stock pilot. I have 13:1, HRC cam, modified lid (cut open but stainless screen over top to keep trash out) Sparks filter and Sparks exhaust with big core. It pulls everywhere. I also cleaned out the head myself. Didn't cut too much on intake side, but I did a little cutting and polishing on exhaust side. Piston gives it bottom and cam gives it top. Excellent for MX.

[Kilabanshee]

Thanks since we both have fairly similar set ups ill give that a try. How does the piston effect your top end? I'm running some 18 inch tires not but was having some ground clearance problems with the longtravel linkage in the rear shock I was thinking about getting some taller tires and possible putting on the stock linkage what do you reccomend?