Stock Polaris 800 pistons

shakenbake · Oct 31, 2014

looking for some info and Advice. we all know the Polaris stock pistons have been junk for some time now. but i have heard that Polaris has improved these pistons year after year for the last 3 years. are they at the point where they are just as good as the pistons in all the Fix kits, or are they still a POS. has anyone updated their stock Pistons with Newer stock OEM pistons in their 800. my is a 2012 S/B assault 144x2 track with 1500 miles on it.

AKFULLTHROTTLE · Oct 31, 2014

So we have two turbo sleds both very close in mileage under 1000 running close to the same boost.

12' Stock pistons both pistons under stock compression but still within recommended specs

13' with RK Tek drop-in pistons, over stock compression

Food for thought though, allthough compression tells you something it does not tell you the whole story. It does not tell you if you have a skirt about to snap off due to excess slop or other issues.

The engines have continued to get better but I also had no issues with my 11. For me its easy, once I install the turbo the warranty is gone so why not put a better piston in it. For me, if I do not have warranty I will install RK's pistons. Love them.

Reg2view · Oct 31, 2014

If you're still under warranty, e.g., a 4 year and you'd like to put new pistons in on your nickel 'just in case' two years in, or you can coerce a dealer to do it for no cost, go with the newest stock.

As soon as you're compelled to replace pistons yourself, out of warranty, go with aftermarket/Wossers. For a 12, no fix kit, no warranty, I'd go with Wossners, and did it for my 11.

RMK935VA · Oct 31, 2014

I believe that the new pistons in the H.O. motor (grooves for increased cooling and lubrication below lower ring on exhaust side) are dimensionally the same as those in the existing motor. I think that those pistons also have some other improvements made to them. If I had to replace pistons, I would consider getting some of those if they are available. These pistons should not void the warranty either.

sledsnowco · Oct 31, 2014

RK tek wossner pistons

tinkerjohnson · Oct 31, 2014

Pistons

Like stated above in my opinion the stock polaris pistons are junk run the rkt pistons they are my choice much smoother running engine and loose the low throttle vibration aswell

rags319 · Nov 1, 2014

I had some warranty work done on my 11 pro. They put in new crank bearings but wouldn't cover pistons. Dealer would only put in OEM pistons in that I paid for. Labor was free tho. Motor still vibrates and sounds like a lot of piston slap. My choice would be rkt pistons.

Braaap12 · Nov 1, 2014

The pistons that came out of my 14 were junk

shakenbake · Nov 2, 2014

Thanks for all the info guys, looks like I will ordering rkt pistons, are guys doing just the pistons, or are you going with the Rtk head as well ???

tinkerjohnson · Nov 2, 2014

Pistons

shakenbake said:
Thanks for all the info guys, looks like I will ordering rkt pistons, are guys doing just the pistons, or are you going with the Rtk head as well ???

I run the drop in kits. I have done all three setups stock replacements and head and both rev one and rev two kits all work well but the drop in kits are really noticeable increase in power, unbelievable throttle responce, but fuel controller is required but well worth it in my opinion

diamonddave · Nov 2, 2014

The Polaris OEM pistons aren't junk. Many have run them without issues. The 13 and newer motors have not had near the issues that people did have with 2012 and prior sleds.

The first and original company that addressed the piston issue in Polaris 800 CFI's was MTNTK back in 2010 which was long before anybody else did. You can call PMS Polaris and get a fix kit for $585. No fuel controller needed. Comes with shim plate that lifts the monoblock, base gasket, new rings and taller pistons. This helps tremendously with distributing the side loads over a larger area.

After installation, you will have better runnability, better longevity, and a smoother motor that will outrun a stock piston'd motor of the same year.

Toolbag · Nov 3, 2014

diamonddave said:
The Polaris OEM pistons aren't junk. Many have run them without issues. The 13 and newer motors have not had near the issues that people did have with 2012 and prior sleds.

The first and original company that addressed the piston issue in Polaris 800 CFI's was MTNTK back in 2010 which was long before anybody else did. You can call PMS Polaris and get a fix kit for $585. No fuel controller needed. Comes with shim plate that lifts the monoblock, base gasket, new rings and taller pistons. This helps tremendously with distributing the side loads over a larger area.

After installation, you will have better runnability, better longevity, and a smoother motor that will outrun a stock piston'd motor of the same year.

That would be a minority opinion for sure. Pistons that do not last 3000+ miles IMO are junk. The only guys getting 3000 miles from pistons are the trail riders. There are plenty of threads documenting out of dimension pistons on '13 and '14 sleds. My '13 has ~1200 miles on it and will not hit the snow this season without getting a set of Wossners from RKT. I would be willing to bet you, cash money, that when I pull the stock pistons they will be out of spec. It wont be because I didn't warm it up, lots of witnesses would tell you I was anal about it, including letting the temp stabilize on restarts. The reason is, the pistons are junk, TONS of evidence to support this, just do a search...

I suspect all of the fix kits work, funny how PISTONS are the main component of the fix kits, don't you think? Being the first one to have a fix doesn't make you the automatic choice IMO. I read the info provided by the vendor, read reviews from users and make an informed choice. I happen to LIKE the fact that RK offers an easy power boost and requires a controller. The new fuel controllers are MUCH better than the early ones an I think the PRO can greatly benefit from richer fuel mixtures. At the end of the day it is lean mixtures driven by the EPA that are HARD on the stock pistons.

I think the ~$1200 it takes to do the RK pistons/head/controller is a nice option. It brings power up to at least equal of my buddies Doo and Cat and should last a lot longer than the stock set-up.

There are several options but, rarely do I see running the stock pistons for over 2000 miles as reccomended. Why would someone use heavier, less dimensionally stable pistons intentionally? Stock pistons are junk.

SU27 · Nov 3, 2014

Asso-Werke?

If new stock pistons are made from soft metal, and by the same Asso-Werke manufacturer, I am afraid Axys owners will run into the same problems as other fellas.
IMHO - stock vs any kind of fix kit issue is pure cast vs forged pistons issue. Whatever you do, forged pistons are always better than cast ones.

Braaap12 · Nov 3, 2014

Not trying to argue or start anything but these are the pistons that came out of my 14 800 with 500 miles, oil added to gas and oil pump turned up from day one, if you look at the top above the rings you can see where it was wearing from rocking in the cylinder

tinkerjohnson · Nov 3, 2014

Pistons

In my opinion the the quality or manufacture of the polaris pistons are not the problem, it's the design and specs that polaris made them. But they have to make a piston that won't seize ( like the dragon days) that works for all elevations, conditions, temp, riders and meet EPA regulations yes they have made mapping refinements and tightened the pistons up along the way and they have gotten better that's evident, but I think there are better pistons available that are better in design and spec which make better power and longivity. I also believe that adding a fuel controller and fatten up the mapping along with good piston makes the engine perform and live longer and make better power.

Sheetmetalfab · Nov 3, 2014

:deadhorse:

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Stock Polaris 800 pistons

shakenbake

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AKFULLTHROTTLE

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Reg2view

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RMK935VA

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sledsnowco

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tinkerjohnson

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rags319

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Braaap12

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shakenbake

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tinkerjohnson

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Toolbag

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SU27

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Braaap12

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