has any one put different pistons in there pro???

[RKT]

Good subject.

I would like to add.. that having custom pistons mean that you can alter anything you wish.. that includes the alloy, complete piston geometry, and even the forging process.

The forging process is VERY important with respect to how a piston reacts in use.
Inotherwords.. forging is not forging... there are many different components and specs that seperate one forging process from another.. And, again, this will effect how the forged piece reacts under load.

With our piston, we have altered a few parameters in order to get the desired results when under load. With these custom pistons, the piston requires no more clearance than its cast counter-part.. Just check out the size... micrometers do not lie.. In fact, the OEM Polaris pistons are very loose and this is the main reason they break skirts (cylinder and piston).

So, there are changes that can be made to counter act properties that are associated with any process. It just a matter of figuring out what needs to be changed and doing it.

 

[Merlin]

I have installed 3 kits on CFI-4's and 2 kits on CFI-2's. All have never run better.

Dave,


Just out of curiosity, what were your clearances when you installed these kits & have you had an opportunity to disassmble anu of the engines & inspect the pistons since they've been in use???

One can't argue with the track record of these fix kits but I would suspect that their success is owed to the cylinder spacer shim & relocated pin bore more so than the piston itself.............


Thanks,


Glen

 

[AKSNOWRIDER]

If you still have warranty couldn't you just re nik the cylinders to proper tolerances with a new set of OEM pistons? It's not the cheapest option but your warranty would still be intact. There's nothing wrong with the Polaris pistons when they fit without excess clearance.

you could indeep..except you have to control the cylinder going out of round as it heats up..ideally, you would have your boring/honing bar setup to bore a cylinder that has torque plates on both sides to simulate the block and head(cylinder distortion just from bolting it togeather) as well as be running 180 degree water thru the coolant passages to simulate what the cylinder sees under a load on the hill...pretty tough to do...so that when the motor is ran, as it heats up under a load, the cylinders come round, which is when its most important.....but yes, you can just have a good stock cylinder reniked, then hone to a closer tolerance..but what is that tolerance? how do you determine what is tight enough, but yet loose enough to not score?

 

[AKSNOWRIDER]

Dave,


Just out of curiosity, what were your clearances when you installed these kits & have you had an opportunity to disassmble anu of the engines & inspect the pistons since they've been in use???

One can't argue with the track record of these fix kits but I would suspect that their success is owed to the cylinder spacer shim & relocated pin bore more so than the piston itself.............


Thanks,


Glen

Glen, most likely you are right, its the cylinder spacer/raised pin that is doing more for longevity then the piston(although give mnt tec credit, they got a piston design that is helping..)......

 

[Merlin]

(although give mnt tec credit, they got a piston design that is helping..)......

That it is, that it is.................


Maybe they're having Wiseco manufacture the pistons with a size on size fit(.000" clearance) & when they receive the pistons they squeeze the skirts in a vise to obtain .005" clearance??? J/K


Seriously though, the track record of their product speaks for itself & they should be commended for building an affordable kit that addresses Polaris's shortcomings.............

 

[ditch1000]

Good subject.

I would like to add.. that having custom pistons mean that you can alter anything you wish.. that includes the alloy, complete piston geometry, and even the forging process.

The forging process is VERY important with respect to how a piston reacts in use.
Inotherwords.. forging is not forging... there are many different components and specs that seperate one forging process from another.. And, again, this will effect how the forged piece reacts under load.

With our piston, we have altered a few parameters in order to get the desired results when under load. With these custom pistons, the piston requires no more clearance than its cast counter-part.. Just check out the size... micrometers do not lie.. In fact, the OEM Polaris pistons are very loose and this is the main reason they break skirts (cylinder and piston).

So, there are changes that can be made to counter act properties that are associated with any process. It just a matter of figuring out what needs to be changed and doing it.

Kelsey,

When a guy adds your drop in kit and head to the Pro, do they have to add weight to the primary to maintain the same rpms???

 

[doobie]

kelsey can i run your pistons with my PAR 3000-6000 ft head?

 

[RKT]

kelsey can i run your pistons with my PAR 3000-6000 ft head?

We have 2 different sets of pistons.. 1 MUST run our special head and WILL produce some great power gains throughout the entire power band and will work with several aftermarket pipes and will solve an internal piston desgin issue that is present with the OEM piston.

The other piston solves the piston issue whilst adding some performance and can be run with ANY head...

Both address an issue and both help with performance.. But the drop in kit adds more performance than our direct replacent piston

 

[RKT]

Kelsey,

When a guy adds your drop in kit and head to the Pro, do they have to add weight to the primary to maintain the same rpms???

That has been the consensus, Yes, But it all depends on the clutching used...

Here is a read you may be interested in: http://www.2strokeheads.com/RPM vs. HP.htm

 

[ditch1000]

Interesting read...Good info, thanks Kelsey.

 

[diamonddave]

Dave,


Just out of curiosity, what were your clearances when you installed these kits & have you had an opportunity to disassmble anu of the engines & inspect the pistons since they've been in use???

One can't argue with the track record of these fix kits but I would suspect that their success is owed to the cylinder spacer shim & relocated pin bore more so than the piston itself.............


Thanks,


Glen

They all averaged about 0.0065" piston to cylinder. The only one that I have watched closely is my personal sled. I have removed the Y-Pipe and head 2 times and reeds once over the first 350 miles and everything looks perfect. Of course removing the cylinder would tell a much better story but I don't see the need.

I have a 2012 Pro coming in next week with 400 miles that will be getting a fix kit installed. All of my work get's road tested (or snow tested) before it gets released to the owner so my personal sleds don't get many miles.

 

[Merlin]

They all averaged about 0.0065" piston to cylinder. The only one that I have watched closely is my personal sled. I have removed the Y-Pipe and head 2 times and reeds once over the first 350 miles and everything looks perfect. Of course removing the cylinder would tell a much better story but I don't see the need.

I have a 2012 Pro coming in next week with 400 miles that will be getting a fix kit installed. All of my work get's road tested (or snow tested) before it gets released to the owner so my personal sleds don't get many miles.

Thanks for the info...............One simply can't argue with positive results...........

If you ever have the opportunity(or need) to pull the cylinders it'd be very interesting to know if the pistons retained their original dimensions measured at the skirt................


Glen