CP pistons

[GPracer2500]

Anybody running a CP piston? I don't know much about them other than what can be learned from their website. The few prices I've seen indicate they are expensive (almost 2x a JE or Wiseco??), but the do appear to be a very nice piston with some unique design features.

Comments?

http://us.st11.yimg.com/us.st.yimg.com/I/yhst-97708346553978_1901_3226081

http://www.racer450.com/issue_05_09/breakerbar/cp_002t.jpg (http://www.cppistons.com/)

[MarkyNark]

Ive run CP pistons in my DS with no problems. I currently run a JE in my EX. Both are good - I have no problem with either one.

[Iliketogofast]

They have really deep valve-cutout-things. I wonder what that's for.

[cals400ex]

i have ran 2 different CP pistons in my 450. i paid $245-$250 for each of them. however, there were a lot of different things done to these than the standard shelf pistons. i have used only CP in my 450. ih the 400ex we have used ross, je, and wiseco. none have really given us any major issues. the wiseco's piston pin was always hard to remove after we ran the piston in a bike. maybe it didn't have the best oiling grooves near the pin area. i never really inspected it that close.

[swva400ex]

the deeper the valve grooves the higher the compression.

[atvn]

The valve reliefs are there for valve clearance. The deeper the relief is cut into the piston the more valve lift you can run. More valve lift equals more air flows in or out.

The valve reliefs also have to be cut deeper on pistons that have a dome or (pop-up) shape. That shape is what increases your compression ratio by reducing the volume in the combustion chamber.

The more depth a valve relief has the less compression the cylinder will have that is why it is important not to purchase a piston with reliefs that are cut much deeper than needed.

This goes back to making sure you match your components during a build so you can maximize the power output.

[cals400ex]

deeper valve reliefs are not always wanted. if you go deeper you lose compression. to regain compression you need a larger dome. flatter domes will be a bit more efficient, thus making a little more power.