HOW TO TELL IF YOU REALLY GAINED SOME POWER!

OK, Hopefully you have read the Article on why clutching RPM changes do NOT really tell you if your latest and greatest addition gave any REAL performance gain.. If, you have not read it, please, take the 5 minutes to do so because it will allow this article to make more sense.

OK, here we go… So, we know that you can NOT rely on your clutching to tell you whether you added performance with your new addition. So, how does one determine if the hard earned money you spent was worthwhile? SIMPLE.. you determine this by testing it in the REAL WORLD.. ON THE SNOW.. where it really counts.. Not on a dyno but on the snow!

Let’s back up a bit with a bit of “common sense” reasoning and theory.

1)ANY internal combustion engine MUST be loaded in order to produce max power. Free-wheeling or unloaded engines simply do not produce. Remove the belt from your engine, rev the engine, and your ears will tell you that there is no real power being produced without the load applied to the crankshaft.  ALL dyno tests are done using a “LOAD” to load the engine. Otherwise, the max torque outputted could not be measured.

OK.. Same applies in the real world (on the snow). You must place a load on the engine to make the engine produce. The heavier the load, the more internal heat is produced and that heat is converted to power via the engine.

Example: Take 2 new trucks.. 1 gas truck at 400HP and 1 diesel at 400HP, get on I-70 in Nebraska and line them up.. What happens? Well.. they run very even.

OK, same 2 trucks, now put 8,000 lbs of trailer behind each. Same I-70 in Nebraska.. Line them up.. What happens now? Well.. The diesel runs much faster than the gasoline truck. How can this be? We just ran them without the 8,000 lb load and they were equal.  Answer: LOAD.. Once loaded, the truck that can MAINTAIN power performs better than the one that is struggling to maintain the power.

NOW, take it one step further, same 2 trucks, same 8,000lb load but now take them to 8000ft elevation on a 5% uphill windy grade that goes on for 10 miles. Line them up.. What happens?? Well, the diesel truck is at the top eating lunch before the gasoline truck crests the top with an overheated transmission and near over-heated engine. Again… LOAD changes everything!

So, 3 different scenarios with NOTHING changing but the load applied to the engine/vehicle and you have 3 VERY different outcomes in terms of “how bad” one outperforms the other. NOTE: the HP/TORQUE of either engine never changed.  Just the manner in which it was tasked changed.

Next time you hear about the amount of "lengths" one gained with ANY product. PLEASE ask them how it did under a heavy load.

SAME applies with snowmobile performance. UNTIL you place the sled in a heavy load situation, you will not always be able to determine if the performance is better or worse than the stocker.

EXAMPLE:  2 identical snowmobiles other than one has some power enhancement modifications (ie. pipe, head, pistons etc.) Line ‘em up on a road. What happens?? The mod one may or may not run faster in a short distance. It all depends on how the sled is clutched and if the current clutching calibration allows the sled to benefit from the added power. In other words, it may be hard to determine if there is a power difference between the 2 sleds.

OK, take them to a meadow with 2 ft of powder.. Line ‘em up. What happens?? Probably about the same as what happened on the road comparison with the mod sled probably running a tad faster. Still, it MAY be difficult to differentiate between the 2 in terms of power.

OK, take them to them to a BIG hill with 3ft of fresh powder and about 1000 ft of hill to pull. THIS is where you will see whether you actually added some power or not! These sleds have the same tracks and chassis. They are identical in every way except for the engine changes. No need to line ‘em up.. Just try and get to the top of the hill that is in front of you.

NOW, you can see the results of the engine modifications.

IF there is truly power added, there will be a NOTICEABLE difference in how high up the hill one sled is able to achieve vs. the other. Absolutely, NO QUESTION, providing both are running at proper RPM and all clutching is healthy, the sled with the more power WILL be higher on the hill… EVERYTIME! 

The higher powered sled will always be able to out climb the lower powered sled. While it may not be able to out “race” it on the flats or in the meadows, once the LOAD is placed on the engine, the added power will be revealed.

OK, we also hear about the “midrange” power enhancement that may accompany a performance product. Midrange power is always welcome and can make your sled more enjoyable to ride due to more “snappy” throttle response. Again, great stuff and welcome, for sure. BUT… midrange power is power that is achieved at BELOW peak operating rpm. So, if your peak power operating RPM is 8200, midrange power would be in that 6500-7500 RPM range. You know.. the “crusin’” RPM. So, if your riding style favors a lot of “crusin” then this type of power enhancement would be a great thing to have. BUT.. Please do not mistake ANY gain in midrange RPM power to translate to PEAK RPM power gains. These are VERY different. Gains realized at midrange RPM are not necessarily realized at PEAK RPM.

Ask yourself, when you are racing across the field or climbing that big chute, are you running at PEAK RPM or MIDRANGE RPM?  Last time I checked the tach, I was not climbing ANYTHING in the midrange RPM. If I was, then the climb did not require much power.

So, not to worry, most products that give your some good PEAK RPM power gains also give you midrange RPM gains as well. The reverse is not always true. You can have products that boost midrange RPM yet give little to no power at the PEAK RPM.

So, be sure that you know what RPM the product you are considering dropping your hard earned $$ on benefits the RPM range that favors your riding style

Polaris CFI-2 Engine and why you may NOT want to warm it up too long”

I have been holding on writing about this for some time because it is going to be very controversial..

But, I believe it is time to discuss this..

What I am talking about is this whole "idea" that letting your sled warm up until it hits "X" degrees before taking off on it is a GOOD IDEA!

This ,MAINLY, pertains to the Polaris CFI engines.

We all have heard and read about how the sled owner lets the sled warm up to 120+ degrees before ever getting on it and how this is a "good" thing..

I am going tell you that this is NOT a good thing and actually can be very bad for your engine.

I am not telling you to pull the sled off of the trailer and PIN IT!..

Hopefully, this article will clarify what I am trying to relate.

1) Without getting into Physics and the laws of thermodynamics (not the intent here), let's touch on the FACT that HEAT ALWAYS travels to COLD.. Hot "anything" will not seek out something that is hotter..

This is very important to remember when reading this article.

2) Your coolant temp is not ALWAYS a good indication of how "hot" the rest of your engine components are (see #1 above)..

Hotter coolant temps tell you that it has removed HEAT from your engine and transferred it to the cooling system.

It does NOT tell you that your engine is SAFE to run at high loads!

AGAIN… we are not trying to dive into ALL of the aspects to what is happening internally.. That would be far too vast and boring to capture anybody’s interest.

This article will be kept VERY SIMPLISTIC in its nature and, YES, any good physicist will, most likely, be able to find “holes” or “exceptions” within the content.

It appears that it is very common to pull into the unloading zone, start your sled, then proceed to get dressed while your sled is running.

Once dressed, you go to your RUNNING sled , check the coolant temp, see that it is at or above 120 degrees F, then jump on the sled and floor it out of the loading area.

With this particular engine design, this, IMO, is a very bad idea!!!

WHY??? OK, let’s try and break it down in very simplistic terms

1) See #1 and #2 above…

2) With this engine, AT IDLE, the oil pump is supplying little to NO OIL to the engine. So, all the time your engine is “warming up” it is near starved of oil.

THIS IS NEVER A GOOD THING… EVER!

3) The engine is heating up, the pistons are expanding, the internal temps are ,somewhat, stabilizing (trying to obtain a state of equilibrium with its surroundings) and the engine is transferring some of its heat energy to the cooling system.

Any oil that was present on the cylinder walls and the piston itself (to provide the NECESSARY oil film barrier needed for a 2 stroke engine to survive) has been completely removed or reduced to an un-safe amount to provide an adequate film protection layer/barrier.

In other words… your engine’s piston and crank-shaft are heated to a high level that is not desired for the amount of oil that is present.

NOTE--> The ONLY way ANY piston can seize in an engine is to have the oil barrier removed.

As long as the oil barrier remains fully intact, you can not seize an engine.

OK, back to the subject at hand…

4) The rider, “eye-balls” the temp reading, sees an acceptable number and “feels” that the engine is now in a “SAFE” state for WOT running…

With this confidence in mind, he/she grabs a handful of throttle and “peels out” of the loading zone heading to the “good stuff”

THIS IS WHERE THE PROBLEM SURFACES!!

5) The engine has just been subjected to HIGH RPM and possible pro-longed running with a cylinder and crank that have little to no oil barrier/film on themselves or the surrounding components…

NOTE--> This is the same scenario when new pistons are installed and the owner decides to let the engine do SEVERAL “Heat Cycles” in the garage after prolonged idling ... Not a good idea either! But that is a whole other topic!

Let’s break it down a bit further….

5a) The engine’s oil barrier is near depletion, the piston and crank are very hot . The cooling system is also at a high temp reducing its ability to successfully REMOVE heat from the engine.

The piston relies on this oil barrier to form a “coating” on itself and the cylinder wall. This oil barrier MUST be present to avoid Metal to Metal contact between the piston and the cylinder wall.

It may be good to note that the cooling system OFFERS the engine cooler running temps SOLEY by giving the engine an outlet to REMOVE its heat.

Many think that the cooling system is actually “COOLING” the engine by surrounding it with cold temps. This is not the case … The engine is removing some of its heat energy via the cooling system... see #1 above.

OK, on with the scenario....

5b) The throttle is “cracked” and the piston is immediately accelerated. Internal temps and pressures begin to elevate VERY quickly! With these higher pressures and temps (not coolant temps but engine temps), the oil’s function is of extreme importance!

5c) But wait… we are, severely, lacking in this oil dept!... NOT GOOD!!

5d) Due to the throttle lever being open past idle, the oil pump is supplying a higher volume of oil to the LOWER END ONLY! There is no direct oil supply path, in this engine, to the cylinder walls!!

This is another issue with this engine’s design.

5e) Oil supply is increased but, keep in mind, at 8000RPM the piston is making 133 revolutions PER SECOND!! And it takes time for this newly supplied oil to reach the cylinder wall and adequately coat it with the REQUIRED barrier (more than a few seconds worth of time).

So, the piston ,in say 3 seconds, has made near 400 revolutions with little to no oil between it and the cylinder wall.

WHAT HAPPENS???

5f) During this short time, the piston has grown even more because the heat of the piston has increased.

The piston is relying on the oil film and fuel to help cool it back to a better level and protect it from making aluminum to NikaSil direct contact.

BUT, the oil film is lacking and the hotter piston begins contacting the cylinder wall at small “points” along the cylinder wall TRYING to fuse itself to the cylinder wall.

This process continues until the oil can get in there to do its job.

The oil barrier is not able to form as easy on the intake side of the cylinder or piston… WHY? Because the piston and cylinder,at BDC, is such that the oil is scraped off the piston skirt via the cylinder skirt (another design issue IMO)

OK… What is the end result of all this??

The end result is that the intake side of the piston will become lightly scored due to its prolonged attempts (sometimes successful) to fuse itself to the cylinder wall.

NOTE: This intake scoring does not affect HP or reliability in any way, providing there is NO material transfer, ring stiction, or “scrapers” produced on the piston skirt from this experience.

OK, I know what you are going to ask... “Why is the stock piston not as prone to this intake scoring?”

That is a very good question.

Here is the answer: The Stock Polaris pistons suffer from skirt collapse VERY quickly. The intake skirts will collapse inward as much a .006” over a very short period of time. With this added piston to cylinder wall clearance, it is much more difficult to make contact to the cylinder wall for reasons that are apparent.

With this excessive clearance, the piston will develop “rock” and “lever” itself against the cylinder wall. This has been a known problem with the OEM pistons. This causes the cylinder to eventually crack and break causing catastrophic engine failure!!! It has also been shown to crack the lower intake CYLINDER skirt.

This is the main reason why Polaris thickened the cylinder skirt on the 2013 and newer cylinders.

OK.., How do you avoid this??

Here is what we suggest:

1) Run about a 200:1 premix of oil in every tank of fuel.

2) Install a better vented oil cap to assure a steady flow of oil to the pump.

3) Turn up the oil pump lever screw a couple of turns.

4) When you arrive at the loading area, start your engine, let it idle for about 2-3 minutes MAX. Your coolant temp will vary depending on the day. But, hopefully, it will be in the 80-90 F range after this.

5) Pull it off the trailer and SHUT IT OFF!!

6) Get dressed or do what you have to do before leaving for the day.

7) When ready to start the day’s ride, start the engine, let it idle for about 1 minute. Get on the sled and leave the area using VARYING throttle (NO Pro longed WOT running or hill pulls) until you get about 1 to 2 miles out of the loading area.

8) After #7--> Ride it as you see fit!!

Using the above method will make for a longer lasting engine.

WHAT REALLY HAPPENS WHEN AN ENGINE “COLD SEIZES”

OK….. The, infamous, “COLD SEIZE”.. This has always been a big concern related to the 2 stroke engine. BUT.. What is REALLY happening when your engine experiences a cold seize?

Is it caused by a mad rush of colder “coolant” passing through the hotter cylinder??

Is it caused by you not letting your engine “warm up”?

Well… Let’s dive into this “mystery” and look at what is happening.

1^st off.. we need to touch on a LITTLE bit of physics and the laws of thermodynamics. We will simplify these principles so as not to bore anybody and then get right into the “meat and potatoes” of what is happening internally.

There are several methods for heat to transfer anywhere. These methods are well known and can be proven very easy. Let’s list these methods:

1)Conduction:  Direct contact of 2 or more objects at different temps.

2)Convection:  Heating of a gas or liquidà Like your forced air home furnace.

3)Radiation: Infrared electromagnetic radiationà Space heaters for example.

4)Vaporization:  N/A

One can make a case for methods 1 and 2 being utilized in a liquid cooled 2- stroke internal combustion engine.

OK, One very important concept to remember à Heat will always transfer from HOT to COLD. Heat will never seek the “Hotter” path but, always the “Cooler” path.

The piston/cylinder area is the heat source and will be the hottest whenever the engine is running. The cooling system will ALWAYS be cooler in temp. ALWAYS!

Your Coolant temperature will always be equal to or colder than the piston/cylinder temperature. This is important to remember!

Heat will always be in the form of energy. Heat is energy!  It is little molecules dancing around (vibrating) and in motion.

OK.. The 1^st law of Thermodynamics is a MAJOR player here. It is VERY simple and , I Promise, we will not dive into anymore physics after this!

1^st Law of Thermodynamics: (robbed from Wikipedia)

This states that energy can be neither created nor destroyed. However, energy can change forms, and energy can flow from one place to another. The total energy of an isolated system remains the same.

A quantity of heat that flows from a hot body to a cold one can be expressed as an amount of energy being transferred from the hot body to the cold one.

So, simply stated, when one object cools, another object in its general vicinity heats as a result. Heat (energy) does NOT just disappear! It is transferred to another object. Equilibrium is the goal.

WHEW!! Now that is all out of the way…let’s relate this to our engine.

OK, We have a piston, crank, and cylinder as a heat source.

We have a cooling system comprised of heat exchangers, anti-freeze, water, pump, hoses, and sometimes even a fan trying to REMOVE heat from the engine’s heat source.

We KNOW that heat always transfers from hot to cold. That this transfer can not create or remove energy and that the TOTAL heat energy present in this “SYSTEM” will remain the sameànone lost and none gained.

Now.. finally… we are at the “COLD SEIZE” Topic!!

One widely held belief is that a Cold Seize is the result of “mad” rushing cold coolant contacting the HOT, running, engine and the result is this cold coolant is shrinking the cylinder walls in a manner such that the hotter piston will immediately fuse itself to the cylinder walls. This is VERY unlikely!!

WHY?? Well.. see what we talked about above.

Let’s look at a few similar scenarios..

Example #1: You are in Antarctica and you build a fire in the frozen tundra and snow. The outside temp is -30 F BELOW ZERO and the temperature of the fire is 1800 F. The fire is giving off heat energy and you and the surrounding air are absorbing it and getting “hotter”. NOW.. you decide to construct an igloo around the fire. You KNOW that the igloo is at least 32 F, if it were not it would not be frozen solid!

Now, as a result of this igloo, the air inside is warmer and you are warmer… BUT the FIRE is still at the SAME 1800 F Temperature. You have surrounded/encompassed the fire with a structure that is at least 32 F yet the fire is still burning at the same temperature.

Sound like anything else? Say… an engine (fire) and a cooling system (igloo). Point being, just because you surround a heat source with a cooling source does not make the heat source “colder”.

Example #2: You have a stove burning a gas flame. You have a large empty pot on the stove. The pot’s walls are getting very hot. You now dump cold water into the pot. Did the flame get colder because of this? NO. Did the pot’s walls get colder? Yes, slightly, but most of the heat went directly into the water. Remember, heat always travels from hot to cold. The cold water did not cool the pot’s walls, the cold water absorbed the heat energy from the pot.

Same with your engine, the coolant removes heat from your cylinder. Since this energy can not be created or destroyed (1^st Law of TD) the colder coolant is becoming HOTTER and heating very quickly while the heat source (engine) temp is remaining the same.

NOW, IF you could surround and engine with cold coolant and the coolant did NOT absorb the heat energy (heat up) and remained cold.. you could then have an issue with a cold seize. BUT.. This will NEVER happen! The coolant will always  increase in temperature and increase VERY rapidly until the coolant and what it surrounds are near or at the SAME temperature causing ZERO shock to any component. THIS is the REALITY!

OK, We have all heard of this “cold shot” on the Polaris 800 CFI and one can see where the coolant temp gauge will increase after you turn off the engine then after you sit for a bit, fire up the sled, and ride, one will see the coolant temp begin to drop significantly. 

What is happening with this?? Simple… When you turn off the engine you have a “system” that never reached equilibrium. You have an engine that is much hotter than the surrounding coolant medium. When you turn off your engine the heat source is no longer active, we KNOW heat ALWAYS transfers from hot to cold. You have a hot engine and a colder coolant medium. The transfer of heat is present and the coolant becomes heated from the radiating engine ALL in attempt to achieve equilibrium. Many will have you believe that your engine is getting HOTTER when this is happening, when, in reality, your engine is getting COOLER (remember the 1^st Law of TD).

So, your engine is NOT heat soaking but is actually cooling down.

OK.. So, you decide to fire the engine back up and you notice the coolant temp begin to rapidly drop. You think… OMG… I am shocking my engine with this cold, cold coolant… Well... Remember the 2 examples above and the 1^st Law of TD? You are doing nothing of the sort. The heat source (engine) is active again and is MUCH hotter than your coolant. The coolant is being heated by the engine NOT the other way around!

 Well.. WHY is the coolant temp lowering? Simple.. while you sat with the engine off, your engine as a “SYSTEM” strived to reach temperature equilibrium (everything is the same temperature). Your cooling system was also doing the same. The hotter heat exchangers and stagnant coolant was trying to reach equilibrium with the cold outside air and snow. They (the heat exchangers and held coolant) are cooling down transferring their heat energy to their surroundings (air and snow) and the result is that their temperature dropped.

NOW  Once you fire up the engine ALL stagnant areas now become active and things are all moving again. The heat source is actively heating its surroundings and the water pump is actively pumping the coolant through the entire system. Stagnant becomes Active! The system as a WHOLE is trying to reach temperature equilibrium and temperatures will be changing.  

What is surely NOT happening is that your piston is getting COLDER! It is getting HOTTER and no rush of cold coolant passing by is going to change that!

OK It should be clear that it is VERY unlikely to have ANY coolant cause enough rapid cooling of a running engine to seize it… NEAR IMPOSSIBLE! Simply because the "magnitude" of the heat source is simply too great for the ,smaller, cooling source to over-come. It is like a spider  vs. your foot!

So.. What does cause an engine to cold seize?

Glad you asked… A cold seizure is the result of the piston expanding too fast with respect to its cylinder.

Your engine is constructed on many different types of materials all housed together and designed to work as one system. All internal engine components, when heated (running engine) will expand to some extent. This expansion is normal and unavoidable. Different components will expand at different rates and will expand to different extents.

When you fire an engine after it has been able to completely cool down to a state where all internal components are at their “NEUTRAL” state.. meaning they are in no state of any expansion due to heat, these components will begin their expansion all over again. It is THIS expansion rate differences that will cause an engine to “Cold Seize”. So, you have an entire engine that is being heated and, as a result, ALL of its internal components are expanding at different rates. This INITIAL expansion is what you need to be mindful of to avoid a cold seize. Once these engine components have reached their full expansion, then the engine should be operating in its design spec and safe to run and run hard. If you choose to fire up a cold engine and immediately pour large amounts of heat into the components (i.e. high rpm) you RISK having these varying expansion rates collide and seize. Make sense??

Cold Seizures have nothing to do with cold coolant passing over a hotter engine!

You, simply, can NOT seize an engine from cold coolant passing over an already "up to temp" running engine!

COLD Seizures DO relate to the varying expansion rates of the different components within your engine. Once these components are at their operating temperature, they will remain there and function as designed.

NO rush of cold coolant would/could adequately change the temperature OR DIMENSIONS of any of these components ,as long as, the "fire" (engine) is still "flaming"

Polaris Piston Myths vs. facts and "Fix Kits"

POLARIS CFI ENGINE MYTHS vs. FACTS

With the Polaris CFI Engine (ALL 2 Injector Models, Including the HO (AXYS)), the lower half of the engine is dry.. meaning there is little to no fuel entering there.

FUEL (NOT COOLANT) is the #1 cooling agent for ANY Engine (important to remember) and this engine has none!

 Heat is one of the primary causes of skirt collapse and skirt collapse is ONE of the primary issues with the OEM design..

Remember this, VERY IMPORTANT, a compression check will tell you little to nothing about the health of your skirts.

You can have a BROKEN off lower skirt and the compression reading will not change!

Doing a compression check will not yield any relevant information regarding the health of your PISTON SKIRTS.

People always state "I pulled my OEM pistons and they LOOKED fine and compression reading was still in spec!"

LOOKING fine and MEASURING fine are 2 VERY different things!

You MUST MEASURE the piston in order to determine if the piston is "GOOD".

Skirt collapse happens usually WITHOUT any scoring or visual appearances on the piston. In other words.. your piston can LOOK perfect but MEASURE out of spec.

Our CUSTOM pistons (Direct replacement, Drop In, AND Big Bore) are CUSTOM designed!

They have very a proprietary design that is unique to ALL of our pistons.

These pistons, we offer, are FAR from ANY "off the shelf" OR "aftermarket" piston available today!

They are 100% unique to RK TEK!

They are also lighter than the OEM Piston and that will help with the acceleration from a stop.

Another VERY important misconception... It is a widely held belief that the OEM Polaris

pistons are too small from the factory and this is where the issues lie with the OEM.

The OEM Polaris piston is 100% in spec and the proper size when new in the box!

The REAL issue is that the OEM piston does not REMAIN in spec after use. 

The other major issue is the LACK of lower  piston support at BDC.

We address this with our REV 2 Drop In Kit.

We are the ONLY company that has a kit to aid in lower piston skirt support.

When you hear that all these aftermarket kits have a tighter tolerance than the OEM.. it is simply NOT true!

 The truth is that the OEM piston's tolerances are in spec, they just don't stay there!

Our custom pistons HOLD their tolerances!  AGAIN.. Visual inspection will tell you NOTHING about the size of your piston.

The piston kits we offer (some call a fix kit.. we do not) are the highest quality piston on the market today.. They are designed with hard anodizing on the ring lands, pin boss and crown underside AND custom coating on the crown.

Installation of ANY of our pistons will allow ANY Polaris CFI engine to reach a higher potential. THESE pistons address many issues associated with the OEM design (Balance, weight, ring location to name a few)..

Turbos also love them!

"FIX KITS" Or other "Clever" marketed named Kits

These are very clever marketing terms to impose the "idea" that by installing these kits that the engine is "fixed" and will no longer be prone to failure.

This can be very misleading!

The TRUTH of the matter is that MOST of these "Fix Kits" are nothing more than an Arctic Cat 800 Piston under a different name.

 If it uses a 1/4" shim under it, then this is most likely the case.  Sorry guys... this is the reality!

Some will also have you believe that they have installed a "special" pin offset. The truth is that the Factory OEM Piston has a .020" offset to help relieve thrust pressure near Bottom Dead Center (BDC).

One would hope that any of these other pistons would also contain this same OEM offset. Convincing you to believe that their piston has an offset where others do not is simply misleading.

Let's get a little more specific:

1) The 2008-2012 Pro 800 CFI Engines use a crank manufactured by MAPE. This MAPE crank has a high failure rate of the lower rod bearing and the outer bearings.

The MAPE crank was discontinued in 2013 and newer engines in favor of a new manufactured crank by FUJI. This FUJI crank is a superior crank to the MAPE in every way.

This FUJI crank WILL install without any modification into any 2008-2017 engine case. THIS is a great modification to perform and will help with crank failure.

Clever named kits do not address the MAPE Crank Issues!

2) The 2008-2009 CFI-4 engines had a VERY thin lower cylinder skirt that was prone to cracking especially once the OEM piston gets lose in the bore.

In 2010 Polaris thickened up this skirt.  Polaris thickened up the skirt, again, for 2011-12 CFI-2 Engines.

ALL of the 2008-2012 800 Engines were prone to lower cylinder skirt cracking!

Installing ANY clever named piston kit will NOT fix your thin walled cylinder skirts!

3) For 2013-Present (HO included), Polaris thickened up the cylinder intake skirt, once again, to help alleviate all the cylinder skirt failures.

This thicker skirted cylinder WILL install into your 2011-2012 cases ONLY if you modify the upper case half to accept the thicker skirt. This is a great modification and can be done by any competent machine shop. This allows your 2011-2012 engines to run with the better 2013 cylinder.

4) There is a common belief that the 2013 and newer engines have a cylinder or crankshaft offset compared to the earlier years. This is 100% false!!

5) It is also believed that there exists a Rod-Ratio issue with the Polaris 800CFI engines. More clearly, the rod ratio is too small for this engine.

The Rod-Ratio is the ratio of the rod length to the stroke of the engine. The longer the rod, the higher the ratio, given the same stroke.

The Polaris rod is approx 132mm in length and the stroke is 70mm yielding a rod-ratio of approx 1.88.

The Arctic Cat 800 has the approx 130mm Rod and the same stroke. Therefore, the rod ratio on the Arctic Cat 800 engine is WORSE than that of the Polaris 800 engine.

The Ski Doo 800HO and 800R engines have a 132mm rod and 75.7mm stroke yielding a rod-ratio of 1.74.

So, it stands to reason that IF the rod-ratio of the Polaris 800 CFI engine is too small, then the rod-ratio of the Arctic Cat and Ski Doo 800 engines are also too small (especially the Ski Doo since it is even smaller).

Based on these FACTS, I think it is safe to assume that the rod-ratio is not an issue and claiming that is nothing more than a scare tactic.

You can derive your own conclusions.

6) ANY running of the thinner walled cylinders (2008-2012) can lead to stress and fatigue on the cylinder skirts. This stress is amplified by a looser piston and the potential for full cylinder skirt failure increases when a piston is out of tolerance .

Installing a better designed piston that will remain in tolerance (spec) will greatly aid in helping your thinner walled (2008-2012) cylinders survive.

Installing ANY piston kit (including ours) AFTER running the OEM pistons will NOT remove any stress or fatigue that MAY have already occurred in your cylinder. In other words,  IF your cylinder is fatigued, it will STILL be fatigued once a better piston is installed.

7) Another held belief is that the new AXYS piston has addressed the OEM short-comings mentioned above.

The new AXYS piston is basically, the SAME piston with some added oil retention grooves on the exhaust upper skirt. This is not a bad change but does very little to aid with the skirt collapse, extreme piston weight, and heavy ring drag.

 We feel this piston to be mildly superior to the previous piston but also feel it is a lesser quality piston than what we offer.

It has EXCESSIVE skirt taper.. This allows for a lot of rocking in the bore (not good)

It also is VERY heavy!

Running our piston vs. this piston WILL show some performance enhancements.

600 Polaris Pistons

1) The 600 Polaris Engine is a great engine!.. However, the piston design is not much better than the 800 Piston.

It suffers from skirt collapse and it is also WAY too HEAVY!

There are some massive gains to be had by drastically altering the piston design.

We have, also, spent the time and developed a Piston Kit and a Drop In Piston/Head kit for the 600 Twin..

Both of these kits offer SIGNIFICANT performance enhancement and extend engine life!

Hopefully, this article will clear up some of the mis-conceptions that surround this engine and its internal design?