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The Get your FIX for the RMK 800

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R44guy

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Additional Get the FIXX Kit Info

Here is the original post from PMS Polaris / MTNTK as seperated by Diamondave and then copy and pasted.

Originally Posted by MTNTK

I appreciate the comments on our products, but there are a few things your not getting quite right. Polaris built this motor to be very compact and lighter than previously designed engines. This being said there were compromises made that they thought were "acceptable".


One of those were to shorten the piston as much as possible. This kit is not a rod ratio change nor does it fix a rod ratio. it does not use pistons with a higher rod location to allow a longer rod to change thrust loading. Nor has any of our research found that the polaris engine had improper thrust loading on the piston.



If the thrust loading problems were true, then you and i would have seen scoring and piston damage on the thrust side of the pistion/cyl. I have never had a problem with the thrust/intake side of the piston. It always looks good, but the exhaust side looks really bad. But it is interesting to look at the design of the polaris engine, because it looks like an engine that they were trying to eliminate rod thrust loading because the stock piston has a rod pin location that is high on the piston almost like they were trying to get the longest rod possible without getting any deck height increase.



What our kit does do is raise the cylinder up and allow us to put a taller piston in the cylinder. What we found is that the polaris engine has excessive piston to cylinder clearance. this allows the piston to rock in the bore effectively using the top and bottom edges of the piston instead of the entire bearing surface of the skirt.


I have a very reliable source that stated polaris had a severe piston heating problem in the prototyping of the engine and so they elected to go with increased clearance to prevent piston seizure. This heat problem was fixed with the ecu reflash. The clearance combined with the piston design causes the piston to scrape the cylinder wall on the compression stroke, especially the exhaust side.


This is why the piston looked like it ran out of oil on the exhaust side but not the intake. This is why the engine would never totally fail, just slowly start to run bad, not going into reverse and then hard to start and then put, put, put and barely back to the trailer. This is also why there was an interesting phenomenon that when using a turbo on this engine it would last longer than stock. Everyone thought it was a fuel issue, but it was not. It was a piston size problem. The turbo added heat and the piston grew taking up the clearance.


The taller piston benefit can be easily described by the analogy if you have a smart car(which is a very short car!) on a single lane highway it would be much easier to turn around without going off the road than it would be to turn a tractor trailer semi (a very long vehicle)around on the same road. The piston does the same thing. It can't move away from the cylinder wall nearly as easy if it is longer and has tighter clearance than the stock piston. This makes horsepower in more than one way.


The first way is because the piston is not leaned over it holds cylinder pressure longer and makes the power stroke longer. The second way is the piston is 40 grams lighter so there are not as much parasitic losses internally. Third and less known is the piston slap is reduced and excessive piston slap can set off the detonation sensor and back off timing. fourth is the previously stated crankcase volume increase, which has been proven in numerous sae studies with tuned pipes is almost always beneficial for engines designed for peak power.



On our dyno it made 4.9 hp more and that was on a totally stock 2010 engine, airbox, and fuel. I hope this sheds some light on the product and I hope you can have some faith in it that we don't just come up with some gimic or "widget" and sell you on it. We test, we prove, we cannot sell you something we do not believe in. I welcome any more questions. Shawn, Mountain Tek Performance.
 
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R44guy

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tjmcc,

I too would like more feed back, Shawn from PMS said that they have been testing this kit fir about 1 year now with no known failures so far, I talked with highmark rentals out of west and he said they have been using them now and even though they dont have much time on these kits he said the engines sound better even at idle.

I would love to hear more info from some one who has been running this kit for sometime. I will be aat PMS Polaris getting this installed this coming monday the 10th. I will be riding my sled all week long so I will let you know how it works.
 

thefullmonte

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I know that just from adding the wiseco pistons to my sled it sounded notibly better. Much smoother. And I have felt that the clearance has been an issue from the start. PMS just takes it a step further.
 
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dub

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Mar 15, 2004
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This is a good thread, let's keep it going!

I will have a kit installed next week on an 09D8. We will post results as soon as we have something. I know that the mag side E-valve will be out after every ride for inspection!!
 

Top Notch

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I should be getting my kit in the next couple days, Will get it put in as soon as possible. I willing to go out on a limb on this one, Hell I did when I bought this POS. After a few visits with Shawn and Bill at PMS, I think this will be a good venture. R44Guy let us know how the install goes, how it runs, and how you broke it in. Thanks a bunch!
 

thefullmonte

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Nov 26, 2007
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Monte,

How long have you had your wiseco pistons and how many miles on them? Did you notice any measurable higher compression since these pistons fit better tolerance wise.

I only have about 300 miles on them. Just haven't been having the best of luck lately so I haven't been able to ride yet.
It does pull over harder. It has a lot more THUMP each time it pulls over. I can't tell you exactly what the compression is. I had to borrow a friends tester originally to see that at sea level I only had 119lbs with the oem pistons. I'm only guessing, but I would say it is a solid 125 at least. Again at sea level.
Sorry I'm not more help on that.
 

Top Notch

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I got my kit today, It'll be going into the shop next week to get put in. Hopefully I can get some seat time on it soon after to see what it runs like. R44guy, You'll get your kit in before mine, please let me know if anything other than what the instuctions say needs to be done. Thanks in advance.
 
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2strokes_are_awesome

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Dec 8, 2007
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This thread has great info but I'd still love to hear feedback from anyone using this fix. My 08 went down about a week and a half ago, 200 miles after update.

Can anyone tell me if I'd be able to reuse my monoblock? The ports look good and the scoring isn't nearly as bad as it was when the original top end burned down. I've got some pics of the cylinder that I can email if somebody would/could take a look for me.

Please pm me if you want to see the pics
 
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R44guy

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Get the Fixx Kit

Topnotch,

On Monday morning I dropped my 09 D8 off at PMS Polaris, No it is not owned by some chics. PMS stands for Performance Motor Sports in Aston ID.

I spoke with Shawn in service and he was very knowledgable about the kit and what needed to be done. I also had some other mods done by them at thee same time which I will explain shortly here.

I also rented a 2011 Polaris ProRide RMK 800 with the 155 inch track and I was pretty impressed. It did not have as much power as my D8 before the kit was installed but it did not matter it went every where that my D8 went and more. It does have a nice mid range power band.

Ok enough about the pro, I picked my D8 up on Tuesday am and had a chance to put 40 miles on it here in Island Park yesterday and not only does it sound better but it also sounds a little different like my old edge rmks.

I also had PMS plug off my variable exhaust valve soleniod hose and replacing the springs. I also had the orignal 08 head reinstalled with the orignal 08 fuel map. Currently I am still breaking the top end in but it not only runs stronger then ever but it feels and sounds strong.

I will update everyone here again later today after todays ride. If you want to check out the youtube video of one of my buds with his helmet cam on while riding the pro see the link listed below.

http://www.youtube.com/watch?v=RDZD3FAoeSA
 
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R44guy

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The get your fix Ride Report Update

I put over 120 miles on this kit so far and it has not missed a beat, This sled sounds better and runs better then ever before since the fix kit from pms polaris was installed a few days ago.

I am very pleased with this kit so far. I also pleased with changing the variable exhaust springs to pink and plugging of the vent lines to the soleniod with the information provided by the fullmonte.

A small ball bearing was pressed into the line going to the soleniod. This is not the same way monte closed his off. I followed montes advise since I also wanted to keep the heat out of the engine.

This has also rid my sled of the little tick, or hick up, and pop that would happen when the variable exhaust valve would start to open and close right away under mid to light throttle, the other bonus here is that it gave me a little more low end power.

Now if only the VR issues were resolved I would feel a little better. But for now I finally have some good engine peace of mind but only time will tell.

I will continue to update this thread after I have my PCV and pipe reinstalled on the dyno and I will let you all know how it did. If you have any questions just let me know. I will post some pics soon to show how the plate sits under the jug.

FYI, also my 2010 updated stock pistons all ready had some wear with just over 113 miles on them.
 

Top Notch

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Kit Installed

I put mine in tonight, I'll agree with you on it sounds alot better. Just a little bit of warm up time on it and it idles on its own and will go into reverse without shutting down. actually pretty simple to do. Looking forward to getting some snow time on it soon. Thanks for the updates R44GUY.
 
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R44guy

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TopNotch,

Please let me know your feed back from this kit after you run it for sometime, I broke my upper end in for 100 miles as recommended by PMS. I ran oil in the first tank of gas. I also had my ethanol wire unplugged until the first 100 miles were on it and I had nonethanol premium 91 octane available.
 
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tjmcc

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I got the extended warranty thank god. first problem I had with it was this year I blew a shock and burned down my mag side with 2600 miles on it. Original warranty was expired 3 months ago
 

Top Notch

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So after getting the sled all back togather and doing a couple heat cycles, I put about 20 miles on it tonight. This sled has never been able to spin over 8000 rpm's, And that was with 62g weights, Now I have 68g in there and a quick blip of the throttle and hit 8150! Rode a few more miles varying the rpm's. Over the course of the ride 2 more times of a good blip it hit 8250 once and 8200 once. Didn't want to grab a handfull of throttle just quite yet, But it was hard not too. It does run stronger than previous. I'm running 2nd from newest flash, PC5 and have the ex port unplugged and back to normal. I am still thinking of putting the gizmo on yet, some more input from peeps who have the PMS kit and gizmo would be great.
 
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