It would seem from the majority of posts that I've read on this topic that JE pistons are better than Wiseco pistons. However; it also seems that a lot more atv people use Wiseco pistons than JEs. I asked a local performance shop about the differences (they sell both)- the guy said that JEs have looser tolerances between the piston skirt and cylinder wall. I've heard that Wisecos are more likely to sieze- perhaps due to the tighter fit?

Anyone out there know more about this topic? Any other pistons worth noting?

 

Wiseco pistons are forged and tend to expand faster than the cylinder which causes them to seize. PRO-X and ART also make pistons.
ERIC

 

The wiesco and the pro-x pistons are both good...
Yet they have different "character" if you will...

 

Wiseco are forged and will reqire a looser cyl/piston clearence because the piston will expand. The chance of a cold seizure is higher with this because they need to be warmed up thouroughly before ridden. The Niks (Pro-X) is a cast piston and wont expand as much so a tighter cyl/piston clearance can be used. Warmup time isnt as critical as on the Wiseco. The Niks is more durable but at the cost of some slight power.

 

If I remember right Weisco owns JE and Weisco is the lesser of the two.