FYI..NEW Product Announcement. Polaris 800 Direct Replacement Pistons

[indydan]

Rod Ratio

Hold on a Minute here, Lets not confuse things.

Pistons do not change rod ratios.

BUT, Piston wrist pin location....... ( be it vertical adjustments or offset from center ) does have an effect of piston life on certain motors depending on the bore & stroke and rod length.

But you cannot " fix " rod ratio with a piston.

A short rod is a risk.......... it allows for tight case volume & a very compact motor. There has been no-problems with 64mm stroke & very few with 68mm stroke.

BUT with the 70mm stroke the short rod has started to show its short comings.

 

[RKT]

Hold on a Minute here, Lets not confuse things.

Pistons do not change rod ratios.

BUT, Piston wrist pin location....... ( be it vertical adjustments or offset from center ) does have an effect of piston life on certain motors depending on the bore & stroke and rod length.

But you cannot " fix " rod ratio with a piston.

Very true...

While I respect Dan's opinion and experience.. again, OUR findings show that there is no rod ratio problem.. Would I prefer a longer rod or, even better, a longer stroke on this engine? You bet.. and I suspect that is coming next year (longer stroke.. that is)... But the current bore and stroke combo have been around for a long time and seems to work well.

The Cat 800 engine, which is very solid, actually has a SHORTER rod than the Polaris and the same bore and stroke. Yet, we do not see any issues with this engine, in fact, it could be the most durable engine out there today!! Yet, the rod ratio with it is worse than the Polaris engine. So, why doe sCAT not have a rod ratio problem but Polaris does??


Look... We looked at the issues hard and have addressed them as WE saw fit and kept it simple and affordable..

If you are not a believer, then this kit is NOT for you.. I have no problem with that.. We have seen the results and are very pleased. It really is that simple.

Kelsey

 

[Sailor Jerry]

Holy chit --Pandoras box has been opened let the games begin.
Poo rider against Poo riders for talking smack about a poorly designed engine
Aftermarket against aftermarket trying to fix said engine
Polaris Ceo and engineers sitting back waiting for the dust to settle than cashing in $$$$
I hope we end up with a well deserved engine and Poo sends someone a big fat check for fixing something they can not or will not address.

Warranty on this engine does not cut it there should be a recall instead on all 800 that have gone down due to piston and skirt issues.

What Beamslayer said!!!

A recall on the 800s that have gone down due to piston and skirt issues, would be a great opportunity for Polaris to put their money where their mouth is with regards to there being "almost zero running issues with the Pro". If there really are as few issues as all the Poo reps/dealers claim, then it shouldn't be that costly for Polaris to recall the dud 800s...

 

[indydan]

Good Post Kelsey.

Very true...

While I respect Dan's opinion and experience.. again, OUR findings show that there is no rod ratio problem.. Would I prefer a longer rod or, even better, a longer stroke on this engine? You bet.. and I suspect that is coming next year (longer stroke.. that is)... But the current bore and stroke combo have been around for a long time and seems to work well.

The Cat 800 engine, which is very solid, actually has a SHORTER rod than the Polaris and the same bore and stroke. Yet, we do not see any issues with this engine, in fact, it could be the most durable engine out there today!! Yet, the rod ratio with it is worse than the Polaris engine. So, why doe sCAT not have a rod ratio problem but Polaris does??


Look... We looked at the issues hard and have addressed them as WE saw fit and kept it simple and affordable..

If you are not a believer, then this kit is NOT for you.. I have no problem with that.. We have seen the results and are very pleased. It really is that simple.

Kelsey

As I do respect yours. Very well said. ( good post Kelsey.)

And you are correct Suzuki most often finds a way to make things work with attention to detail.

And I have not said a piston change will not help these motors, I believe the FIX & Your piston can make things better. ( have not personaly run either ) But the one thing that does happen when a new piston combo is offered is the piston to wall clearnace is addressed and corrected if needed.

Where as a motor that is repair by a large majority of the dealers that are not required by polaris have a cylinder bore gage or even train them how to use one to many motors are slapped together with new pistons in bores that are completely junk & out of spec. ( I have a $25,000 cylinder hone ) Dealers have a drill in a parts washer with a snap-on ammco hone. ( Junk to say the least ) .

And I am sorry for jumping on this thread but I do know polaris would not have these problems with piston wear if the rod ratio was better.

Cat has played a few tricks in motor design that Polaris missed by a mile.

And cost will make my option less desirable then a piston change. ( My choice of repair is costly & is not for everyone. )

Dan

 

[Angermangement890]

The PMS kit addresses both the rod ratio issue and the sloppy piston dimensions. There should be some Dragons with that kit with some big miles on them by now.

The PMS kit does NOTHING to alter the rod ratio of the stock 800 CFI engine. A rod ratio change can only be acheived by altering the connecting rod length or the stroke of the engine.

The PMS kit uses a taller piston than stock with a lower pin location to help stabalize the piston in the bore.

The tolerance that the Wiseco's are held to for roundness and sizing compared to the stock pistons is most likely where most of the benefit is seen in the PMS kit. An engine with .008-.012" PTW clearance is going to see a huge improvement in power/reliability when the piston actually fit the bore like the PMS kits wisecos do.

 

[Angermangement890]

Hold on a Minute here, Lets not confuse things.

Pistons do not change rod ratios.

BUT, Piston wrist pin location....... ( be it vertical adjustments or offset from center ) does have an effect of piston life on certain motors depending on the bore & stroke and rod length.

But you cannot " fix " rod ratio with a piston.

A short rod is a risk.......... it allows for tight case volume & a very compact motor. There has been no-problems with 64mm stroke & very few with 68mm stroke.
BUT with the 70mm stroke the short rod has started to show its short comings.

A short rod ratio does allow the engine to rev quickly. This is the reason that the 797 engines that Polaris produced for SnoCross used a 70mm stroke with a 128mm rod. They rev'd fast and when combined with a LIGHT forged piston allowed for very fast throttle response. They did not have a long life, many teams replaced pistons on a by heat bassis for peak performance. The exhaust side of the piston always showed the most wear and ocasionally the rods would break in the middle of the beam, or a piston skirt/cyl skirt would break and take out pretty much the whole engine... sound familiar?

The 64mm stroke Polaris Engines use a 128mm rod, rod ratio of 2.0 and a 77.25mm piston. Very few rod issues and guys in mod form turn these engines to 10,200 RPM.

The 700 CFI engine uses a 68mm stroke, 128mm rod, rod ratio of 1.88 and a 81mm piston.

The 800 CFI engine uses a 70mm stroke,132mm rod, rod ratio of 1.88 and a 85mm piston.


In addition to the Rod/ratio on the CFI 800 being shorter/lower than previous 800's the piston weight is significantly higher than the 700 CFI which shares the same ratio, the 70mm crank travels an additon 2mm in comparison to the 700 so the 800 piston gets pulled lower into the case, combine the greater mass and more travel and you get more skirt loading than a 700 with the same ratio.

Very true...

While I respect Dan's opinion and experience.. again, OUR findings show that there is no rod ratio problem.. Would I prefer a longer rod or, even better, a longer stroke on this engine? You bet.. and I suspect that is coming next year (longer stroke.. that is)... But the current bore and stroke combo have been around for a long time and seems to work well.

The Cat 800 engine, which is very solid, actually has a SHORTER rod than the Polaris and the same bore and stroke. Yet, we do not see any issues with this engine, in fact, it could be the most durable engine out there today!! Yet, the rod ratio with it is worse than the Polaris engine. So, why doe sCAT not have a rod ratio problem but Polaris does??

Look... We looked at the issues hard and have addressed them as WE saw fit and kept it simple and affordable..

If you are not a believer, then this kit is NOT for you.. I have no problem with that.. We have seen the results and are very pleased. It really is that simple.

Kelsey

But Polaris has only used this "Sweet 132mm rod" from 08-12 and all the failures we are currently discussing were produced in that range.


Suzuki has a different Wrist pin placement in the piston than Polaris, a different cylinder/piston skirt shape and the cylinder skirts are about twice as thick as the Polaris.... Bet that has NOTHING to do with their longevity.

Could you also please post the answers to the orginal questions I had????

 

[Rally2]

Some great info coming out now glad to see this thread pull out of a nosedive. I've got my '09 800 Cat motor topend apart at home right now; on Tuesday evening I can get some pics and measurements of the pistons/cylinders for interest. One thing I won't be able to measure is the rod length, anyone know how long the Cat 800 rod is? I know the bore/stroke are same as the CFI800.

 

[INDEEP]

A short rod ratio does allow the engine to rev quickly. This is the reason that the 797 engines that Polaris produced for SnoCross used a 70mm stroke with a 128mm rod. They rev'd fast and when combined with a LIGHT forged piston allowed for very fast throttle response. They did not have a long life, many teams replaced pistons on a by heat bassis for peak performance. The exhaust side of the piston always showed the most wear and ocasionally the rods would break in the middle of the beam, or a piston skirt/cyl skirt would break and take out pretty much the whole engine... sound familiar?

The 64mm stroke Polaris Engines use a 128mm rod, rod ratio of 2.0 and a 77.25mm piston. Very few rod issues and guys in mod form turn these engines to 10,200 RPM.

The 700 CFI engine uses a 68mm stroke, 128mm rod, rod ratio of 1.88 and a 81mm piston.

The 800 CFI engine uses a 70mm stroke,132mm rod, rod ratio of 1.88 and a 85mm piston.


In addition to the Rod/ratio on the CFI 800 being shorter/lower than previous 800's the piston weight is significantly higher than the 700 CFI which shares the same ratio, the 70mm crank travels an additon 2mm in comparison to the 700 so the 800 piston gets pulled lower into the case, combine the greater mass and more travel and you get more skirt loading than a 700 with the same ratio.




But Polaris has only used this "Sweet 132mm rod" from 08-12 and all the failures we are currently discussing were produced in that range.


Suzuki has a different Wrist pin placement in the piston than Polaris, a different cylinder/piston skirt shape and the cylinder skirts are about twice as thick as the Polaris.... Bet that has NOTHING to do with their longevity.

Could you also please post the answers to the orginal questions I had????

Good info. I should have said the PMS kit addresses the rod ratio issue by lowering the wrist pin location relative to the pistons overall length. I installed one on my Dragon and dumped that pos. I personally think this kit will outlast the crank but that's another story.

 

[RKT]

Good info. I should have said the PMS kit addresses the rod ratio issue by lowering the wrist pin location relative to the pistons overall length. I installed one on my Dragon and dumped that pos. I personally think this kit will outlast the crank but that's another story.

With all due respect.. this was an informative thread about a new product.. It was not about comparing one kit to another..

IF you want to have a direct comparision, then maybe one should start a thread to compare the specifics of the available 800 kits..?? But this thread was not initiated to be a comparision thread.. merely, a new product release thread..

Can we try and keep ti that way?

On the side note...The taller piston and raised cylinder does NOTHING to effect rod/ratio nor does it significantly alter the loading.. In fact, the piston will have LESS support when and where it needs it the most... Not more... The distance from the pin to the piston skirt bottom does not change and can not change

Wouldn't you agree Dan?

Again, if you want to get in depth on the differences, I think a new thread would be in order...

ALSO the Ski Doo engine has an even worse rod/ratio and a cylinder skirt that is very thin.. YET... it has no skirt or piston breakage... go figure!!

 

[GREICO1]

With all due respect, your original post should have not included anything about Dan's kit if your intention was not to be a comparisin. You opened this door and now you need to close it. Your pistons, and Dan's kit, may offer solutions to the issues that are being seen, or they could both be band aids to cover a deeper rooted issue. Either way, the forum should thank you for your offerings, stop bashing and poking at each other, and move on. You have pistons coming. Great! Dan has a kit, Great! We will see next year if anyone has truly found a way to increase the longevity of our current 2 stroke motors, or if we should take a page out of the MX bike maintenance manual and just go through our motors every 1000 miles, and replace the wear items that we should be so we can quit bitching, and keep riding.

 

[RKT]

With all due respect, your original post should have not included anything about Dan's kit if your intention was not to be a comparisin. You opened this door and now you need to close it. Your pistons, and Dan's kit, may offer solutions to the issues that are being seen, or they could both be band aids to cover a deeper rooted issue. Either way, the forum should thank you for your offerings, stop bashing and poking at each other, and move on. You have pistons coming. Great! Dan has a kit, Great! We will see next year if anyone has truly found a way to increase the longevity of our current 2 stroke motors, or if we should take a page out of the MX bike maintenance manual and just go through our motors every 1000 miles, and replace the wear items that we should be so we can quit bitching, and keep riding.

AHHHH... There is no mention of Dan's kit anywhere in my posts...

Please do not read more into writings than is actually there..

Again.. no mention of Dan's kit anywhere

 

[GREICO1]

From what I have seen here, he's the only one who has said anything about the rod ratio. Again, close the door.

 

[Angermangement890]

With all due respect.. this was an informative thread about a new product.. It was not about comparing one kit to another..

IF you want to have a direct comparision, then maybe one should start a thread to compare the specifics of the available 800 kits..?? But this thread was not initiated to be a comparision thread.. merely, a new product release thread..

Can we try and keep ti that way?

On the side note...The taller piston and raised cylinder does NOTHING to effect rod/ratio nor does it significantly alter the loading.. In fact, the piston will have LESS support when and where it needs it the most... Not more... The distance from the pin to the piston skirt bottom does not change and can not change

Wouldn't you agree Dan?

Again, if you want to get in depth on the differences, I think a new thread would be in order...

ALSO the Ski Doo engine has an even worse rod/ratio and a cylinder skirt that is very thin.. YET... it has no skirt or piston breakage... go figure!!

I've asked some questions about this new product that you have yet to answer. I reposted them below... Interested in the product, but want more info as to how/why these are better than stock units.


Does the Ski-Doo engine have all the other issues the Polaris does and do they use the same piston, wristpin location, skirt design, Is the cylinder made by the same manufactuer and does it share all the same design features the Polaris does? How about the stroke, bore etc? Doe they have the same guy doing QA at the cylinder manufacturer, how about the piston manufactuer? No?... then comparing Polaris to Ski-Doo is pretty pointless. And as Dan alreasy stated, the devil is in the details and the folks at Rotax know how to work the details.

If I remember properly, the ski-doo uses a 75.7mm stroke and a 82mm bore. Piston weight affects the longevity as previously stated. Don't post well so and so has a worse rod ratio and then leave out pertinent info, like the fact they use a piston that most likely wieghs 80+ grams LESS than the one your comaring to and its 3mm smaller in dia. Leaving out info like that makes me think of Shady car salesmen. While were at it, what is the connecting rod length of the Ski-Doo engines?

Ill add another question, what is the weight of your piston compared to a stocker, weighed with wristpin, circlips and rings.

The questions I still would like an answer to:

Will this drop in kit require a reflash of the ECU to perform properly?

What RPM will the new drop in piston kits operate at?

How does the powerband of the Polaris engine with your pistons change?

Is the clutching and RPM you run with these pistons the same as stock or are other modifications needed?

How does your "Drop In Piston" vary from a Stocker?

Off set Wristpins to reduce side loads? Barrell Shaped Pistons? Different Skirt Shape? More material near the wristpins? Do they have a similar shape to the 2011/12/13 stock Polaris pistons? Do you utilize a Garfal Skirt coating on the piston and a Hard Anodized crown like the stockers? The pistons shown are for your 860 Big biore and are Wiseco?

Are you going to be offering a warranty on the engines that you build/install these pistons on?

 

[tbeaton]

i guess your version of affordable is a bit different than mine. bit more than i was thinking the pistons would cost.

 

[Dirt2oil]

i guess your version of affordable is a bit different than mine. bit more than i was thinking the pistons would cost.

I believe when I put new top end in my pro the cost was between 5-600. I could be wrong tho... The price on Kelsey's was only a few hundred more and it came with a head. If any of this is incorrect let me know.

 

[Jimb]

Kudos to both Kelsey and indy Dan with out innovators there would be no solutions to the problems that manufacturers put their heads in the sand about.

 

[tdorval]

i guess your version of affordable is a bit different than mine. bit more than i was thinking the pistons would cost.

Are you looking at the drop in kit or the replacement piston. It's close to the price of stock I think.

 

[PaulAnd]

I just installed an rk tek drop in piston and head kit in my CFi 4, was in Cooke City last week, my 2010 Assault pulled on every sled in our group, it was the strongest sled period! Outran a 2012 freeride 154 etec 800 that WAS broken in. Runs smoother, way more power than before. Gonna keep it another year now, will post how it does next season, so far I am impressed with this kit.

 

[indydan]

We will see next year if anyone has truly found a way to increase the longevity of our current 2 stroke motors, or if we should take a page out of the MX bike maintenance manual and just go through our motors every 1000 miles, and replace the wear items that we should be so we can quit bitching, and keep riding.

I also read between the lines and thought this thread was a slam. But I am now looking past that. ( The best paragraph I have heard in a long time ) These sleds are like Dirt Bikes and should be trearted that way. The factory's would be alot better off and so would the consumer.

Ok, To address Kelsey's question - Yes I agree that moving the wrist pin down in the piston does not change rod ratio and it does not change side loading.

But I do believe that the correct clearance & wiseco's softer material is easier on the cylinder. ( I still am not a wiseco fan )

I know there are people that just don't want it to break. So that being said I desided to build motor option with a 3 & 5 year warranty. ( That I warranty ) And not some insurance company that tries to wessel out of paying.)

As mentioned on here by a few guys........It seems we all offer an option for the people with very different prices and very different thoughts on how to skin the cat.

Its good to see people getting up in the morning trying to think of a better & stronger way.............Rather then walk to the mail box to see if the working class sent you another check.

Dan

 

[RKT]

I also read between the lines and thought this thread was a slam. But I am now looking past that.

Ok, To address Kelsey's question - Yes I agree that moving the wrist pin down in the piston does not change rod ratio and it does not change side loading.

But I do believe that the correct clearance & wiseco's softer material is easier on the cylinder. ( I still am not a wiseco fan )

I know there are people that just don't want it to break. So that being said I desided to build motor option with a 3 & 5 year warranty. ( That I warranty ) And not some insurance company that tries to wessel out of paying.)



Dan

Yes, all this "reading between the lines" and "inferring" of what people post is just the nature of internet forums..

Just because you think you infer something from the post does NOT make it true..

Bottom line is, that most of the time, there is no need to read between the lines.. just take it in for what it is (face value)..nothing more..

Like Dan says, more than 1 way to skin this Cat.. We have taken different approaches and have differing opinions on what the real issues are. But that is also "par" for LIFE.. If everybody agreed 100% with everybody else, then there would be no diversity...

BUT.. to turn this into some sort of "pi$$ing match" is unproductive and will do nothing...

I will state again, that I do not believe the rod ratio to be bad, It is WELL into the accepted range and I see the issues to be piston and cylinder related.. If anybody else has a differing opinion, I have no problem with that... really! But.. there is no need to turn this thread into a negative.

Kelsey