Hey bubba,
I saw you have a close to 1997 Polaris Sport 400cc. I have a quick question for you, I ride hills, jumps, trails, mud, river bottoms. I am having Rick Ritter rebuild my engine right now, and I was wondering if replacing the stock piston with a Wiseco is the way to go??? I have read so much controversy through different types of pistons and what not, I was just wondering if this piston will last for me. I live in Illinois where we have cold winters and hot summers. Could you please let me know.
Thanks,
J-dogg

 

Oh yeah bubba I have a 1997 Polaris 400cc Sport.
J-dogg

 

I aint bubba but I personally wouldnt put anything but a Wiesco in a 2 stroke or 4 stroke dirt bike.One thing is the stock pistons in 400s have a tenency to break skirts.But if you dont ride hard a cast will work but I dought that you would ride hard [img]i/expressions/face-icon-small-wink.gif[/img] Go with Wiesco it will pay in the longrun. Brad

 

I have 3 of the 400's, and all of them have wiseco pistons in them. They are the leading manufacturer of replacement pistons in the 2-cycle market, and they are definitely the strongest. I wont run anything else. You will notice a little bit more "engine rattle" due to piston noise, but that is perfectly normal. It's not that is is real loud or anything, but just a little more than stock. A forged piston will swell when warm, so just make sure to give the motor some warm up time when riding. A couple of minutes at part throttle does just fine. The fact that it is so much stronger and dont cost much more than a cast to me makes sense to run them. Have you thought about porting that thing? Bubba

 

Bubba, how long do you go before a rebuild or re-ring I'm not trying to start a fight just curious.
My preference is cast pistons but this is in a 250cc motor I've never experienced with the 400's. But I have had more than twice the piston life with my cast piston as my Wiseco forged. Forged is the thing to do in a modifyed motor I would stick with cast if are just doing a rebuile and not any hop-ups, they are find fo the average rider. WSM cast pistons are great I've had myn running perfect the compression hasn't moved for 4yrs almost 5 and it still has good compression, I'm gonna tear it down and put new rings just because not that it needs them. Bubba made good points about the larger the bore the more of a chance you have of breaking a piston. Polaris stock pistons are junk I have had one crack definatly stay away from them. I've never had a WSM cast piston break.

 

I'm not Bubba either (sounds like the beginning of a song [img]i/expressions/face-icon-small-smile.gif[/img]) I normally "freshen" the top end up at least once a year. They can go a lot longer, but for piece of mind, and the best performance......it works for me.


Ken

 

I went to the .140 overbore about a year ago and have not had the top end down since then. Only been on the alky for about 1.5 months. Like Ken says it is really a good idea if you run them hard and ride often to re-ring them about once a season. I would have to say I'm sure any aftermarket piston,even cast, would be better than stock. The whole thing of my previous posting is to stress the use of forged pistons on modded machines. The stock motors only turn 5700-5800. The full race units turn 2000 more than that. That's alot more piston speed. Keeping in mind that the 400 developes more piston speed automatically because of the longer stroke. HPD doesnt even recommend anything but forged with a simple pipe change. I really wasn't too worried on changing my wife's piston until it had a meltdown.[img]i/expressions/face-icon-small-happy.gif[/img] Bubba

 

HEY BUBBA IM A DS650 RIDER ISAW IN THE BOMB FORUM ABOUT THE TACH'S FROM AUTOZONE WILL WORK CAN YOU EXPLAIN A LITTLE MORE THANKS MAN
FROM BOOKEND

 

Hey bookend, I only know of them working on the single cylinder 2-strokes. They will read alot more than they should when hooked up to a 4-stroke single, about 50% more. You have to get one for a 4-stroke single. Sorry, if there is some other way then I dont know. Bubba