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Discussion Starter #1
What do you guys recommend, oem pistons or wiseco, or the wiseco Pro-lite for my 98 xcr 440?
 

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oem...
 

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Personally, I run Wiseco and I don't see a problem with them. I've had good luck untill recently which is party my own fault. But, I would say OEM just because..might as well use what should be used in it. If I knew more about this stuff at the time I decided to get the Wiseco kit, I think I would have said OEM.
 

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The difference is that Wiesco is Forged and OEM is cast. If using Weisco your machine shop needs to add the extra piston to wall clearence for the forged pistons. Weisco is a better piston but I'm not knocking OEM either. Less chance of cold seize with cast pistons. Personal preference I guess. I prefer Weisco.
 

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I put wiseco in my 98 xcr 440, no problems yet. the kit was nice and included base gaskets, head gaskets, and exhaust gaskets. well worth the 250 for the pair.
 

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Search function at bottom of page yields two (2) pages of results using "wiseco".
 

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I run Wiseco's in my 98, but it really wasen't my choice. If I were to do it again I would go OEM, just because thats what that motor was designed to run.
 

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Originally posted by tripplethret
[br]The difference is that Wiesco is Forged and OEM is cast. If using Weisco your machine shop needs to add the extra piston to wall clearence for the forged pistons. Weisco is a better piston but I'm not knocking OEM either. Less chance of cold seize with cast pistons. Personal preference I guess. I prefer Weisco.
I always thought cast expanded fast then forged
 

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Originally posted by xcr_racing
[br]
Originally posted by tripplethret
[br]The difference is that Wiesco is Forged and OEM is cast. If using Weisco your machine shop needs to add the extra piston to wall clearence for the forged pistons. Weisco is a better piston but I'm not knocking OEM either. Less chance of cold seize with cast pistons. Personal preference I guess. I prefer Weisco.
I always thought cast expanded fast then forged
I will have to research actuall expansion rates as you might be right that cast expands faster but it does not expand as much as forged and that is why you need extra clearence with the forged piston.
 

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use spi (i think) or kimpex or oem. i wouldn't use "seizco" in my sleds so i dont recommend them to ANYONE
 

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Originally posted by 98srx700
[br]use spi (i think) or kimpex or oem. i wouldn't use "seizco" in my sleds so i dont recommend them to ANYONE
The only reason they will seize is if incorrect piston to wall clearence is used. Quality machine work will correct your bad experiences.
 

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Discussion Starter #12
Originally posted by tripplethret
[br]
Originally posted by 98srx700
[br]use spi (i think) or kimpex or oem. i wouldn't use "seizco" in my sleds so i dont recommend them to ANYONE
The only reason they will seize is if incorrect piston to wall clearence is used. Quality machine work will correct your bad experiences.
Any piston replacement for a stock cylinder should be undersized properly,your not going to machine a nikked cylinder to fit a newpiston and recoat the cylinder. I'm sure that Wiseco or any other manufacturer has sized the piston to the stock cylinder size. Correct me if I'm wrong
 

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Yes it should be sized correctly but remember it is always up to the builder to check tolerances and make sure they are correct before assembly.
 

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i have never used it because of all the stuff i hear. and i quoted "seizco" from another topic. my cousins iantomasi racing been in the biz or building quality race and trail engione an they told me "never to use wiseco in trail engines, they will seize". so i am going with what they say and i advise this info to others.
 

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I have called them seizco's for a long time now.
Hold a weisco in one hand and the OEM in the other.
The Weisco is that much lighter for a reason, it has that much less materiel.
Now look at the thickness at the piston skirts where you can see the actual metal thickness.
The Weisco's don't have nearly as much materiel.
Now look at the webbing and built in reinforcement in the shape of the OEM in the piston where the wrist pins go in and then look at where none of that is in the Weisco.

This thinner materiel and all is why there needs to be a larger clearance for Weisco.
They do expand that much more when they get hot, and thus, they are that much more tempermental to temp changes, and thus, that much more tempermental to jetting for elevation and ambient temps.
The Weiscos are much more prone to piston slap because of the larger clearance.

I simply won't run them.
Spend the extra cash and get OEM.

Just my not so humble opinion and the reasons for it.
 

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depends which is cheaper. The weisco kits add a little extra pep to your machine (lighter pistons), but make sure its done right (bring it to the local machine shop or engine shop or someone who does it for a living) When I ran weisco in my Dirt bike, it lasted a few weeks and it cold seized on a cool morning (just idling)...Im kinda split on my opinion but you cant go wrong with OEM unless they had a defect for that particular year.
 

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say what you want i have never had any problem with , wiseco's use them ever time i do a over haul ,or a failure with oems,usally a airleak etc ,now i do know some people can ,smash a anvil with a rubber hammer
 

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my engine was done by iantomasi and I use wiseco piston...never had a problem but I make shure to warm it up before pinning the throttle..Its a trail sled it works more than perfect. If you want to you cna use the oem piston but put the wiseco pins in them...theyr are alot lighter and people have told me that it makes a difference
 

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Are you a tuner? or are you a pull-and-go type person? If you are the latter go OEM. If you are the former go wiseco and make sure you have it all set-up properly and always properly warm it up before getting on it. OEM pistons are built the way they are for a reason, they are forgiving and can handle more abuse and bad practices.
 

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Originally posted by Student Driver
[br]I have called them seizco's for a long time now.
Hold a weisco in one hand and the OEM in the other.
The Weisco is that much lighter for a reason, it has that much less materiel.
Now look at the thickness at the piston skirts where you can see the actual metal thickness.
The Weisco's don't have nearly as much materiel.
Now look at the webbing and built in reinforcement in the shape of the OEM in the piston where the wrist pins go in and then look at where none of that is in the Weisco.

This thinner materiel and all is why there needs to be a larger clearance for Weisco.
They do expand that much more when they get hot, and thus, they are that much more tempermental to temp changes, and thus, that much more tempermental to jetting for elevation and ambient temps.
The Weiscos are much more prone to piston slap because of the larger clearance.

I simply won't run them.
Spend the extra cash and get OEM.

Just my not so humble opinion and the reasons for it.
very nice, i could have said it better myself. i guess this adds to my post, more like concludes it.
 
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