Cart empty
Polaris 800 Drop In Billet-1sm
Polaris 800 Drop In Billet-2sm
Polaris 800 Drop In Cheater-1sm
Polaris 800 Shell colors-1sm

Polaris 800 CFI 12HP or 20HP Drop In Kit

Snowmobile Make:
Head Color:
Elevation Unit will be used
Fuel Octane:
Options: (Choose One or More)

2008-Present (AXYS ALSO) POLARIS 800 CFI 12HP or 20HP "Drop In" Piston/Head Kit 2 DIFFERENT KITS TO CHOOSE FROM.


NO FUEL Controller required!! (on 2011-2012 800 CFI Engines (Rev 1 Kit only)

Fuel controller required on the 2013-Newer and ALL REV-2 Drop In Kits )


These Kits work EXCELLENT on the CFI-4 engines . ALl CFI-4 engines will require a fuel controller

NOTE: ALL pistons come with Rings, Wrist Pin, and Circlips!


NOTE: RKT Top end gasket kit is comprised of the Base Gasket, Y -Pipe Gasket, Exhaust Valve Gaskets (Non-HO ONLY), and Inner Compression O-rings. These gaskets are not part of the piston ONLY kit but are available in the options.

You want a dyno report from DynoTech Research... Click on the link below

DYNO REPORT on REV 2 Kit- (2014 800) (<--clicky)

NOTE: The REV 2 kit was designed to give near 100% full lower skirt support for the piston. This lack of lower skirt support is a major contributor to why the stock pistons FAIL!

This piston is designed UNLIKE any other piston out there!

ALL other kits out there REMOVE lower skirt support by shimming the cylinder up.

This kit ADDS lower skirt support!

Please Subscribe to Dynotechresearch.com for the latest in Performance Testing

This kit WILL outperform ANY other "Bolt On" product you can buy for this engine!



We ONLY stock the AXYS Billet Head that uses the larger T-Stat. This Larger T-Stat allows for much cooler running and better performance. For the "Cheater Head" option none of this applies.


Here are the Polaris part numbers and parts fiche link you need to do the conversion for the larger T-Stat

T-Stat:  1206124  #10 on fiche #2

Cover    5140363 or 5140362 (dual coolant out)  #6 on fiche #1

Screw   7520470   #2 on fiche #1

Fiche # 1:   https://www.ronniesmailorder.com/oemparts/a/pol/5a3a5cf987a8660eb45e7c92/engine-cylinder-all-options

Fiche #2:   https://www.ronniesmailorder.com/oemparts/a/pol/5a3a5ced87a8660eb45e7c80/engine-cooling-system-all-options



 The Polaris CFI 800 engine really benefits from a better piston and an engine port timing adjustment.  The RK Tek Drop in Kits provide both of those.

The Pistons are lighter and more balanced. They also have much better ring seal which produces power and keeps your engine cooler (better heat transfer).

We have also incorporated a cylinder port timing adjustment via these pistons.  This allows the engine to produce more power and rev quicker.

Independent dyno reports have shown HP increases in the 15-20HP range. This kit is the “Real Deal”

The better piston design also greatly reduces the “Handle-Bar Shake” that you notice when idling and riding. 

Two kits are offered. Both very different in design and performance. 

After MANY tear-down and inspections, these kits have PROVEN to be solid and, more importantly, to fix the issues that are associated with running the OEM piston.

Serious HP (18HP (Rev-1 Kit) (20HP Rev-2 Kit) is realized and the reliability IMPROVED for a very small cost!

NOTE: The AXYS (HO engine) is more difficult to add HP. The REV 1 kit closer to 12HP and the REV 2 can get 16-18HP BUT will require an aftermarket pipe.

No "gimmicks" that claim to address the issues but really do nothing.

You can NOT get this kind of power AND address an internal engine problem anywhere else for this low of price!


Please be aware of "CLAIMS" that the OEM cylinders are over-sized from the factory!! This is simply a sales "gimmick". We have measured 100's of these cylinders and NONE of them have been out of spec!

It would have required a HUGE final bore machining/boring error for this to happen... again, this is a clever gimmick to try and sale you something!

There is NO problem with the sizing of the cylinders. There IS a problem with the pistons .


Please see below to learn more about our solution!

The REAL "HELP" will come in the form of 2 Custom Pistons and a Custom Head that will completely transform your engine into what it should have been from the Factory!

With our custom piston geometry, the porting is altered resulting in huge HP and Torque gains!

Piston side loading is reduced due to our unique piston's weight. Yes, this piston is lighter than the OEM piston and having a lighter piston will reduce piston side load pressures AND reduce the stress on the crank!

Also find that annoying vibration is gone with these pistons..

You know how the PRO likes to "shake" at low idle?


We find that the OEM Polaris Piston will NOT hold its form after a very short time of running. We have found it common to see the piston to cylinder wall clearance DOUBLE in less than 1000 miles.. THIS is the #1 reason behind these cylinder failures associated with the Polaris Engine!!

IT IS NOT due to a rod ratio error! It is SOLELY related to excessive piston to cylinder wall clearance!

The RK Tek Pistons address this issue 100%!


NOTE: This is VERY important...These pistons have a VERY unique design criteria.

You do NOT have to treat these pistons any different (in any way, shape or form) than your stock piston!

They require ZERO added "treatment"!

They will NOT fail unless they are subjected to a low fuel or high heat condition! These pistons are the BEST piston available on the market today! BAR NONE!


BEST PART: NO AFTERMARKET PIPE is needed! We, purposely, designed these kits to perform using the stock exhaust components!

Once you have the kit installed.. YOU ARE DONE!!


We have been doing these "Drop In" Kits for over 19 years on the Ski Doo and now we are applying our "expertise" to the "lacking" 800 CFI Power-Plant.


There is NO DOUBT that this mod is the best mod for the money you can do.

Reliability is NOT compromised in any way, shape, or form and the cost is VERY affordable.




In fact, we designed this kit to run on the oxygenated fuel (Ethanol) and still use the NON-ETHANOL factory resistor!! So, it extremely safe on bad gas! How great is that?


NOTE: This REV 2 kit WILL require a fuel controller (Boondocker OR Power Commander) AND will require aftermarket reeds (Boyesen or Vforce) AT any elevation BELOW 3500ft. Above 3500Ft. stock reeds work fine but the aftermarket reed systems will work better!

The REV 2 Drop In Kit was dyno'd on 2 different engines (before and after) at Dyno Tech Research in 2014 and 2015 and showed a max power gain of 21HP with the STOCK Exhaust System and 91 octane PUMP GAS!

These reports are posted for all Dyno Tech Subscribers to view.



Call anytime to hear more about this great upgrade


Check out what one customer (who is actually a Polaris Mechanic/Service Manager) had to say after an install

"Hey Kelsey. Put my drop in kit in today, nice stuff. On this sled also all the annoying vibrations and 3000rpm death-shake are gone. Smooth. The stock pistons were 3 grams different in weight. The RK Tek Pistons were a full 27 grams lighter and exactly the same weight to the gram. The old setup when idling the coolant temp would gradually climb of course and continue to climb without hesitation. Your head cools so efficiently that i never could get the temp over 133F it would just sit there. Even when brought up to 4500-5500 rpm the temp would slowly climb to 140F. What an amazing difference. Can't wait for good snow now. Turned the oil pump up one full turn and running 91 octane on the non eth resistor. 1/2 litre of semi synth oil in full tank fresh fuel. Anything else you think i should know bud shoot me a pm when you get a chance, i know your flat out. Have a good one man.
Thank you,"

AND another


There are yet no reviews for this product.

Don'f Forget to Send in Your OEM Heads !

If you are ordering cheater heads, we will need to have your OEM heads to make the modifications.  If you have any questions
call us anytime we're here to help.