Welcome to the board!:cowboy:

 

wiseco makes them ,want to buy a complete motor?

 

Dealer checked Weisco, couldn't find anything for the 425. As far as the motor, I'm not going back with the 425, thanks anyway. I did find a stock piston and rings. I am going to hone the cylinder a try it, if it doesn't work I will probably part it out. Thank's for replying to my post.

 

Check with HIT the Gas. They are a supporting vendor. I am sure they can get the parts. I think your dealer don't know what they are talking about. They want to sell you a new 4 wheeler. You should be able to get parts. Someone must have really abused the motor or ran it hot. The 425 engine is one of the most dependable engines Polaris has. Make sure your camshaft and rocker arm assembly are good.

 

Hi, You are absolutly correct. Nobody makes an oversize piston for a '96 425. No wiseco, shindy, namura, not even polaris. They do however make 2 oversize pistons for the '97 425. I've asked 2 polaris dealers to contact polaris to find out what the difference is as they have identical bore, stroke, and compression ratio. Also the rings, and wrist pin are the same part number. The only response we got from polaris was "no substitue part number at this time". This one little forum thread is the only information i was able to find after scouring the internet. So i took a chance and went ahead and ordered a 97 piston. When it comes in in a week i will compare them side by side. I have used this and other forums as a reference in the past so i decided to join so i can post my findings. hopefully oneday it will help someone. I think it will work. I'm thinking oil control holes or something like that.

 

Well the new piston is in and is way different. Most notably the intake valve reliefs are much shallower and at a different angle. Also it has a shorter skirt and is generally less bulky all over. There is not enough meat on the new piston to cut deeper valve reliefs, I didn't weigh them but im sure the new one is much lighter as well which would likely have a very negative effect on engine balance. If you have a pre '96 425, my advice: dont blow it up.

 

do what I did, put a 500 ho motor in it, youll need a 40 mm carb and carb boots, you can stretch the air box boot, its tight but will work,