I bought a 2001 Polaris Sportsman 90 for my son and it's not running right. I checked the compression and it's around 60psi....time for a new piston and rings. Can I just put in the standard bore piston and rings, or should I bore it out?

 

try putting about a 1/8 cup of oil into the spark plug hole then check compression. if it gets up to around 120 or so i would say i just needs new piston and rings. if it doesnt reach that mark then you need to bore it out.

 

Thanks! I'll give it a try.

 

You can get a topend ki with new cylinder,piston,gasketst from a guy on ebay for less than you can buy a piston and bore it.
And yes you WILL need to bore it.

 

Do you have any information about this guy? Does he have a ebay store?

 

Do a search for Eton 90 pistons check box for titles and description

 

I found the Eton top end kit. Will this bolt up exactly as regular Polaris parts? Will it perform as well as genuine parts?

Thanks!

 

Eton makes the Polaris 90s.Yes it will fit