450 13.1 piston or 500 12.1 setup ????

[2manycrashes]

I think I've finally decided to break into my motor and need some help.

I ride trails, dunes and like to drag. Running open air box, hrc cam, sparks pipe.

With that said, I am confused which way to go on the piston.
I would assume that the 500cc pistion with the 12:1 compression would produce more horsepower than the 450cc 13:1 piston.

I could really use some input on the pros and cons of going either way. In addition to the piston, I will likely have the head ported and polished and a 3-way valve grind done.

I've looked at a number of the 13:1 posts and hear really good things about that mod, but am unclear if the 500 kit is the way to go.

THANKS IN ADVANCE !!!!!!!!!!!!!!!!!!!

[mikes450r]

i was just wondering what 500 kit is using a 12;1 piston..I know sparks 500 kit is using a piston bigger than there 13:8:1

[2manycrashes]

I may have my information a little wrong, I thought that was what I had read about the 500 piston on one of the forums.:confused:

[BIGBLOCKBILL]

The FST 500 kit uses 12:1 compression piston. I have one in both of my R's. You can run them on pump gas with the use of an FST cam. The difference from stock is amazing. It's like a stock 400ex versus a built 440EX.

[Blown 331]

Can you run a FST 500cc piston with pump gas and an HRC cam? I wouldn't see why not?

[kgbg]

Or you can run a 500 13.5:1, and run race gas, and haul ***.
I have on, if anyone is interested....JE 2 ringer.

[2manycrashes]

Originally posted by kgbg
Or you can run a 500 13.5:1, and run race gas, and haul ***.
I have on, if anyone is interested....JE 2 ringer.

KGB,

That sounds pretty good, but I think for now I am going to go with the 13:1 JE 3 ring piston and a port and polish. Maybe later, I'll go massive. :D

[the_hulkamaniac]

Why wait to go massive. IF you get the 13-1 piston you will still need race gas. 13-1 means you want performance so why go 3 ring, more friction less power. With that port and polish, the cam and 500cc 13.5-1 piston you will be done. Throw the money out once and do it right.

[2manycrashes]

while you have a great point, I already bought the piston. And the cylinder is being cleaned up as well.

I was just a little leary of boring out the cylinder to 500 cc and have my fingers crossed that the 13:1 will be a little more reliable.