I'm at the end of a year of riding after installing a Wiseco piston. I'm noticing what sounds like piston slap, similar to what I heard prior to my stock piston skirt breaking. Is the piston slap just inevitable from normal wear no matter what type of piston I'm running? Anyone else notice this with a Wiseco?
My 400 ran like a dream all year but I don't want to push my luck and go thru another piston failure.
I was planning on tearing down the top end anyway as part of yearly maintenance and I was wondering how long some of you guys go between top end rebuilds? Do you do it yearly or just when you have to do it?

 

Crawdad,

I swapped out the stock piston in my Xplorer 400 for a std. Wiseco, and noticed piston slap a few tanks later. I tore the engine down, and sent it to Ritter. He measured the piston and cylinder, and it showed .015" clearance, and is supposed to be set at .003" on a fresh bore. I believe the service limit according to Polaris is about .006", but I'm not positive on that figure.

Right now, I'm just waiting on swaintech to coat a piston for Ritter to bore my jug out to fit it. Mike Chero commented somewhere that he has 2 years on a swaintech-coated wiseco with no piston slap noises, and his is lightly modded. Maybe Swaintech is the answer........who knows?

Later,

Waylan

 

When you first installed the wiseco did you measure clearance? Not all cylinder walls are even, so if you bought a STD size piston and put it in without measuring clearance you may have been way off to begin with.

Other variables like riding style, motor mods, oil used, ect... would determine how often a piston is to be changed. At minimun rings should be changed 1X a year, IMHO. The best way to gauge is to regulary check your compression. Now the specific number you need to look for is going to be based on your engine mods. As piston clearance increases, compression decreases. Based upon those numbers you should set a minimum level, then swap in a new piston once you reach that point.

 

I have seen this happen twice, when the bushings on the primary clutch wear out it sounds just like a piston slap. I would check this before I tore into the motor.