I have a 1995 Polaris 400 that needs to be rebuilt (top&bottom)I bought a Clymer manual but still had a few questions. The jug looks to me like a steel ring pressed into an aluminum houising, do I have this overboard or have it pressed out and a new one put in. Also any recommendation on were to purchase parts wold be appreciated, do they make kits for ATV's like they do cars??


Thamks fo the help

 

It would be cheaper to have it bored and then put in a wiseco piston. This will make it a little quicker and more reliable in the long run. Dennis Kirk .com has everything you need. The 400,s have tons of mods and aftermarket parts for them. Take the jug and get is bored, put piston, rings, bearrings and you should be set. It dont make sense to get it re sleeved unless the grooves are to deep to be machined out. If you do have to get it re sleeved you might as well get an oversize kit. Here are some companies to look at for machine work and aftermarket parts.

www.denniskirk.com for any parts
www.rittercycle.com for any machine work, very reputable
www.hpd-inc for any pipes or clutch kits

 

Just to double check prices, Dennis Kirk can be kinda spendy. Check with Ritter, or HPD, they can probably work you a deal on the piston and bearings. Remember to retorque the cylinder to case bolts once you've warmed the rebuild up.

 

If you can get it miced out to see how much it needs boreing go on ebay and there is a guy who has wiesco pistons for $64 and you can get gasket setys on ther for around $25.The only thing you will need from Polaris should be a new wrist pin roller.This i fairly simple job and costs less than $200 to do.It will need to be bored to the new piston but any good bike shop or machine shop can do that.

 

hey guys,
why is the wiesco better?i redid mine and used oem polaris piston,the dealer told
me it was better?.

 

The Wiseco is forged, where the stocker is cast....forged is much stronger. Also the ports in the Wiseco are huge compared to the stocker, better flow means better performance. While doing this you could also have your cylinder trail ported by HPD or RCR, add a pipe and a clutch kit. The grin factor will increase exponentially!!![img]i/expressions/face-icon-small-smile.gif[/img]

 

As for the differance in pistons the stock ones have been known to break the skirts and mess up a complete engine.As for the porting if you dont send it off to get it ported atleast smooth the rough stuff out and polish it makes a big differance.

 

Ask BUBBA297 about porting. He does a real good job and it would make a big difference on power. He dont take long either.

 

I can verify that OEM piston skirts will break, I just re-built mine last summer because the piston skirt shattered. I was lucky because It did no other damage, but while I had It apart I went ahead and got It ported and bored +.020 and many other things. I now have a Wiseco piston that I found the cheapest on Rocky Mountain ATV along with a gasket kit. Good luck with your re-build.