High Compression Piston

[raceready12]

Does anyone recommend a high compression piston. I was wanting to put one in my 05 yfz but i have been told lots of stories that they wont start. I only have electric start but i plan to put the kicker on my bike. if you do recommend a high compression piston, what brand do you recommend.

[Ride1Rob]

First off, yes! The bike will have problems turning the motor over with a 13 to 1 piston or higher (Not sure about the 12 to 1). All you need to do is upgrade the battery to the YZF R1 or CBR1000 motorcycle battery. It doubles the cold cranking amps and solves that problem. Minimal modification of the airbox will need to be done as the battery is a tad bit bigger.

I have heard some very good things about the CP piston. Myself, I've had 2 JE's and both cracked on me in less than 6months. One did no damage at all and the other caused a part of my rod to break. That did some internal damage to my cases. I will never put another JE in my bike. I am currently rebuilding my bike and going back to a stock 06 piston. As far as recommending one, If you're going to change it about every 20hrs to stay on the safe side you should be fine. I was trying to get 40hrs out of my JE's which is only about 6months of ride time and it would never make it.

[ohsobad_chevy]

Velocity Racing (CP) makes an awesome piston. I would go 13.5:1, but you will have to run race gas to prevent detonation. They are priced higher than JE or Wiseco, but you get what you pay for. I have seen people get many hours out of CP pistons and they make great power. You will be very happy with a CP piston.

http://www.cppistons.com/

http://www.velocityracingatv.com/index.htm

:blah:

[Dr89]

I had a JE 13:1 but i couldn't tell you how it is to tart with the stock battery because like Ride1Rob said, i've got the CBR1000 battery. anyways it took less than a week for the 13:1 to blow a head gasket. I replaced it with a wiseco chrome 12:1 piston and have had it for many months now with zero problems, i also have the crank and rod kit and i easily pull away from my buddy on his 04 yfz with just a slip on. mine also feels a lot snappier through the trails, its worth the money.

[jim_beam_racer]

get a JE 14:1 from rossier its made specially and thats what i got i kick *** on the track but definatly half to get that kicker but when you get it dont try and take wires out you think you dont need (learned the hard way)

[Ride1Rob]

You get that 14 to 1 and you'll be doing more rebuilds than you can imagine.... If you don't have the money to tear that motor down and check things often you're asking for trouble.

[quaddad#123]

We have two 05 yfzs with 13.5:1 JE pistons with very few problems. We had some problems with aftermarket head gaskets but we switched to the YAMAHA gaskets and had no problems. Both quads have stock batteries and no starting problems at all.