Wossner Polaris 800 Pistons

[John 970]

4M Group buy?

Can you fill us in on this group buy?

 

[tinkerjohnson]

And that, right there, is the million dollar question. History tells us we need to decrease the crankcase volume at elevation, but that is assuming the motor is designed with enough volume in the first place. Given the physical size constraints placed on the 800cfi...who knows. Maybe someone smarter than me.

What I do know is that installing any of the "fix kits" on an 800 cfi at anywhere close to sea level greatly improves all characteristics of the motor and they flow more cfm as well and need more fuel. We've probably built over 100 of them in the past 4 years and every one of those sleds ran much stronger than when it had stock pistons. But they also make more compression, 10-15 psi on average. I don't see any of these kits actually losing power regardless of elevation.

i have installed a couple kits in dragons not on pros and they seem to run ok not much better than they were (not bmp but simular) kits one was on a stock sled and one on a dragon with compression and pipe and fuel controller and did get it to run pretty well still not pulling rpm like it should but pretty consistant better than it was before though, but we ride 11000 ft so just trying to figure out if its a good thing on sleds at high elevation

 

[GoBigParts]

I have read a lot of threads on the fix for this engine and all of the data gets very muddy. Some say the problem is 100% pistons. Some say Polaris uses junk pistons. So with this logic it would seem any good piston cast or forged would be better than the stock pistons. Is this correct? Then there are others that claim the pistons are fine and the problem is the rod ratio. Don't want to start an argument on this again but am trying to get a handle on the piston. I see RK Tech, Bikeman, Wossner, MTN TK, Wiseco, SPI, Polaris and probably others all make pistons for this motor.Seems there are at least 3 special designs on the wossner piston for the same motor. Wiseco has their design as well. Has anyone had experience with the Wiseco pistons or even the cast SPI's in the motor?

When warranty redid my top end I got my pistons back. They didn't look too bad but the rings were flaked pretty bad. I also believe the top ring groove was also starting to open up. Probably from the rocking and load on the piston due to poor piston design or rod ratio. Basically got just over 2400 miles on the pistons before changing and before any damaged happened. So with the Wossner or RK Tech could I expect 5000 plus miles? I wonder if anyone really knows? To me a Fix-it kit should last well over the 2000 miles mark or even double or tripple that.

 

[backcountryislife]

So, are the RKT designed pistons exclusive to RKT? The reason I ask is that I've been in contact with a 4M user that has put together a group buy on the RKT piston from Wossner for $250.

Just like how wiseco won't sell you a piston from Speedwerx or some other MFG even though it's made by wiseco, you're not going to get an RKT piston from Wossner themselves. Nobody would take the time to design something if the MFG was going to go behind their back & sell it directly.

Your buddy is mistaken... or getting taken... one of the two if he's claiming this.

 

[swrev]

I run RKT Wossner pistons in my turbo XP and Wossner Bikeman 880 pistons in the big bore XP. Did not purchase them through RKT or Bikeman. There are other vendors carrying these "spec" of pistons. Wether or not they have something worked out w/ RKT and Bikeman, I really can't say. They are awesome pistons though. I'd have to find the sales slip to see how the prices compare.

 

[diamonddave]

Yes, 100% exclusive...

I run RKT Wossner pistons in my turbo XP and Wossner Bikeman 880 pistons in the big bore XP. Did not purchase them through RKT or Bikeman. There are other vendors carrying these "spec" of pistons. Wether or not they have something worked out w/ RKT and Bikeman, I really can't say. They are awesome pistons though. I'd have to find the sales slip to see how the prices compare.

Didn't you see RKT's post above....they are designed by and exclusive to RKT.

 

[backcountryislife]

Didn't you see RKT's post above....they are designed by and exclusive to RKT.

So, I'm curious... do you just go around LOOKING for threads that have any mention of RKT just to Douche them up as much as possible?

Just something I've wondered about. It's not as if you generally bring any solid points to the table, but instead just kind of make douchey posts without much merit to them... it just seems odd to me.

Don't get me wrong, I've got guys I'm not a fan of, but I at least attempt to have comments be pertinent to some issue I've got.

 

[sledhd4life]

I will be happy to try and clear up any confusion that may lie with the pistons we offer

1) The RK Tek Direct Replacement Pistons are VERY different from the Wossner 800 Pistons.. yes, they are made by Wossner but they are VERY different in design. ALL my pistons are designed from a blank sheet of paper and made with custom components (No, they are not 100% Wossner). These pistons, as all my other CUSTOM pistons, follow this same design procedure,

2)The RK Tek Direct Replacement Pistons are also VERY different from the OEM Polaris 800 pistons... but.. I do no think that there was much confusion with that one.

3) The RK Tek Drop In Piston Kit--> Uses yet another custom piston that is very similar to the Direct Replacement Piston in terms of components used and design criteria.. They can be use with the stock OEM head but the engine will NOT run well.. It will not be in any "danger" but it will run poorly. This is a "KIT" one of which we have been offering the likes of for over a decade... The "KIT" requires the piston and head in order to function to its full potential.. This kit will produce double digit HP levels and has been "spotted" out performing MANY much more expensive kits that are offered.. In all honesty, for the money, this kit is the best bang for the buck available today..


You can view the many threads on this forum (and others) that speak to this kit's performance and the 100's and 100's of very happy customers...Just do a search on here and the threads should surface.

We take great pride in innovating new products and implementing new ideas and turning them into reality... The RK Tek Line of Custom Pistons (manufactured by Wossner.. but designed by RK Tek) are one example..

We have a few new "products" that will be surfacing for mid to late season release that will be game changers.. Stay tuned.....

Hopefullly, this clears up any misconceptions that may be floating around.
AS ALWAYS... We are here to answer questions and are just a phone call away at anytime.. Please feel free to call or contact us with ANY questions or concerns.

Kelsey

SO, I just ordered the direrect replacement pistons from you but I have a ultimate PAR kit (head, pipe, fuel controller) and was curious if I should have (or could have) ordered the drop in pistons for more performance.

 

[tinkerjohnson]

SO, I just ordered the direrect replacement pistons from you but I have a ultimate PAR kit (head, pipe, fuel controller) and was curious if I should have (or could have) ordered the drop in pistons for more performance.

you would have to buy his head with the drop in pistons, they require special cut domes so they wont work with your par head. the pistons you ordered will work just fine with your setup

 

[3beans]

Tinker sorry for the bad rep have big fingers.

I don't think Kelsey found any performance gains using a pipe with his kit but I'm not sure what kit that is 858, drop in, or another?

 

[wideopenproductions]

Terra Alps Fix Kit?

Not to hi jack the thread but has anyone tried their fix kit?
http://www.terraalpsracing.com/product/polaris-cfi-800-2008-2013-performance-kits

 

[wideopenproductions]

Terra Alps Fix Kit?

Has anyone tried theirs?
http://www.terraalpsracing.com/product/polaris-cfi-800-2008-2013-performance-kits

 

[tinkerjohnson]

Tinker sorry for the bad rep have big fingers.

I don't think Kelsey found any performance gains using a pipe with his kit but I'm not sure what kit that is 858, drop in, or another?

i wondered why i got a bad rep from you no biggie but yes i tried the slp pipe on mine and saw no change in power some guys say yes, if it does its not much thats on both 858 and drop in kits, stock pipe seems to run best as for the 858 i dont run one but from what ive herd they have best results with stock pipe

 

[Nickitos]

So, wossner (RK tek) piston forged or not?
ps/ krasnoyarsk hi)))

 

[mountainhorse]

Wosner .... RKtek... Forged yes.

The Wosner forged pistons for RKT are made with 4032 forgings. 4032 alloy has a high silicon content.
These pistons are similar in thermal expansion properties to a hypereutectic Cast piston.

Wosner 4032-alloy pistons are different from the 2618-alloy used in most Forged pistons.... the 2618-alloy is what most of the "legend of forged" pistons is based on.

4032 has a high silicon content 11-12% silicon... which makes it much more user friendly... and generally more expensive than Hypereutectic Cast pistons.. and tougher than a cast piston as well because of the forged construction.

The stock pistons are Cast Hypereutectic pistons...with about 12-16% silicon content.

In high boost applications... a 2618 forged pistons works well... but are shorter lived pistons usually reserved for race engines or those that are not expected to stand up to high mileage/hours.... or in extreme high output engines or engines that might detonate, they are less prone to fracturing than Cast or 4032-alloy pistons. 2618 pistons have less than .2% silicon content and suffer from cold seize and other issues commonly attributed to THIS alloy when used in pistons... NOT true of the 4032 alloy.

Skirt collapse is more prevalent in 2618 alloy pistons with long term use... and the clearances in initial setup must be larger than a cast or 4023 piston. That need for clearance also leads to piston slap when cold (which or sleds are most of the time relative to most engines)...That slap also accelerates wear....

The 4032 Alloy in the Wosner pistons does not need to have larger clearances... and runs clearances typically used with Cast piston applications.



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[Nickitos]

Big thanks!) I thought, if i use forged pistons i can't start up engine in cold weather conditions)

 

[mountainhorse]

Big thanks!) I thought, if i use forged pistons i can't start up engine in cold weather conditions)

That is true for SOME forged pistons.. depends greatly on the material and construction of the piston.

I have NOT found this to be true for 4032-alloy forged pistons.








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[Nickitos]

I seen it with wiseco pistons) -20c and engine "say" bye bye))

I have question about spark plugs for 800 cfi, NGK or something better??

 

[SHAWNBRO]

Installed RK Tek direct replacement pistons in my 2013 pro as maintenance at 2100 miles, made it to 2500 miles and the motor seized. Everything is stock. Cant blame it on the pistons, but wish I would have saved my $400, cause now i need new cylinders and pistons.

 

[rydningen]

Installed RK Tek direct replacement pistons in my 2013 pro as maintenance at 2100 miles, made it to 2500 miles and the motor seized. Everything is stock. Cant blame it on the pistons, but wish I would have saved my $400, cause now i need new cylinders and pistons.

Your issue is most likely linked to a lean condition caused by a bad injector or pulling air into the engine where it shouldnt. Or oil starvation.

That picture is not relevant to the thread IMO.