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I don't/won't run Weisco.
They are forged, and so they expand more when they get hot.
They compensate for this by running looser clearences at cold measurement.
This will make them much more prone to piston slap and piston skirt damage than the OEM or Cast pistons.
The forged pistons are also more prone to seizure because of this expansion.

For aftermarket pistons to save a buck, I'd say to run either the OEM Spec ones from the WPS book, or SPI cast pistons.
Don't forget to replace all of the gaskets and O-Rings, rings etc when you do this.[thumb]
 

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There's a lot of discussion on which pistons are best if you do a search on here; forged (Weisco) vs. cast (SPI and others).

Yes, forged pistons have looser tolerances, and yes they need these specs to expand. What I've found out is people who use Weisco and have had bad luck is that they aren't warming up their engines to allow for this expansion - just startup and go. Or, they are not taking into consideration they need slightly smaller size pistons when ordering Weiscos because they are forged and expand when warmed up - a seizure usually the result.

These are just a couple things to keep in mind if you do order Weisco pistons. I've used both forged and cast and haven't had any problems with either.
 

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i like spi

i even have the sticker on the side of my sled lol
 

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at the end of the day OEM is the best, period

I myself never had great luck with weisco, I was going through alot of pistons in a mod and I found the cheapest cast lasted the longest (I think the ones I used were called Jaloto??) sound like winners though!
 

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skidoordie, Im glad you brought this up. I totally planned on ordering a weisco kit for the 488, and now I guess not. God I love this place--learning all the time!
 

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wiseco's in the 800 xcr is .0025" that is a lot tighter than stock.
i have no problem with wisecos other than the cost and care for a trail sled. in a race sled they are the only way to go as well as prox brand.

oem is great but spi's are a tiwan knock off that i have had good luck on many many sleds and they are cheap in price!
 

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i even have the sticker on the side of my sled lol
[/quote]

that ads like 10 horse right
 

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madcow said:
wiseco's in the 800 xcr is .0025" that is a lot tighter than stock.
i have no problem with wisecos other than the cost and care for a trail sled. in a race sled they are the only way to go as well as prox brand.

oem is great but spi's are a tiwan knock off that i have had good luck on many many sleds and they are cheap in price!
Have to totally agree with you i also run Wiseco's in my race engine and SPI for the trail sled.
 

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for ski doo look at the oem piston, some of skidoos came stock with a coated piston that is a lot better than the cheap coating on the spi's.
 

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I think my sled has Naumara (sp?) pistons in it. I WILL not run weisco's in a snowmobile as stated by everyone above. SPI is an awesome piston that has done me good also. Naumara or SPI is my vote.
 

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MaxTrax said:
I think my sled has Naumara (sp?) pistons in it. I WILL not run weisco's in a snowmobile as stated by everyone above. SPI is an awesome piston that has done me good also. Naumara or SPI is my vote.
Yea Namura makes all of the pistons for SPI, SPX, etc. They all have a little N with a circle around it on the inside casting of the piston. Excellent pistons, used them before, will use them again. I have no idea why they run them under a mystery company like SPI and not roll with just Namura. Playing Twighlight Zone music...




Spence
 

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if u run the spi i have herd to run the oem cir clips cause they r stronger, thats what i did. oem is $ but its prolly a better choice but the spi u can get duel rings for a lot of sleds as of last yr
 

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oem coated pistons in my 00 700, If you use oem pistons you have to use oem rings, and should run oem circlips as well. Circlips are not resusable. Ask a dealer that has a warranty on service work if they use oem ar a/m parts.
 
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