Pro Circuit Piston

[TexLaBo]

Has anyone else had any negative experiences with the Pro Circuit high compression piston?

I've had a couple odd experiences with them and I was wondering if anyone else has had problems.

~Tex

04 RMZ

[justarider]

Sorry, no experience with them. Although there's an add in a mag, I looked at it and thought, hmmmm, that looks trick.

[merlinn]

I have one in my bike, seems fine, great power. But, I have not run a stock KX.

Merlinn

[TexLaBo]

I was just curious, because I got one, and it appeared to be undersized. It rattled like it had 10 seasons on it (...yes, all the rings were pointed the right way). They replaced it, and with this latest one, it seems to have better grunt but the lack of rev is more pronounced.

I installed this piston at the same time as the SS valves (..i know i know), and I'm not sure whickh is causing the problem. I don't think it's the valves. It feels l ike the high compression is stuffing it up...not like the valves are dragging it down. But, it's hard for me to tell without switching out the piston for a stocker, and Im just not up for any more tearing down of the motor. I'm sick of it.

Please don't start a whole debate about valves again... my other post pretty much ware out that issue. I just wondered if anyone had replaced their stock piston with a PC and lost a little over rev.

~Tex

'04 RMZ

[scuba821]

if the piston is made of a different cast,meaning heavier it will seem slower.lighter piston will rev faster

[RC876]

I am not a big fan of compression. Its no secret that too much compression will take away overrev. The power gains down low makes it impressive even for a beginner rider. In 2003 e were actually lowering the compression on our Rm125ers to give bigger hp numbers up top.

The RMZ makes gobs of power with just some mild porting and paying attention to detail. I would spend my money there and stay with stock compression.

Norman