RKT pistons and $28 thermostat

madmax · Dec 27, 2016

Bought a couple 15' 800 pro 155's over the summer to replace a couple of my older sleds I sold. First ride out I noticed they ran pretty hot for a 2-stroke, 130-150 degrees. From my understanding the ECU starts to pull power over 130. Both sleds have just shy of 1500 miles. I bought some RKT pistons from Kelsey at the slc snow show. Figured it would be good to try them and freshen up one sled and see how it compares to the other stock sled. Go figure, next ride out, stock piston takes a dump on one sled. Thank goodness still under warranty. So while it's apart at the dealer I give him the RKT pistons to install and the parts for the $28 thermo bypass.
Had the RKT sled out over the weekend. Never saw temps over 120. My other stock sled was 130-140 degrees, pretty deep powder riding. The RKT sled ran smoother, gained almost 300rpm and had noticeably better throttle response than the stocker. Very happy with the results. Used RKT stuff in the past and always been impressed with the results. Thanks to you snowesters on the $28 bypass info.

peaceofwork · Dec 27, 2016

Is their any thing special about the rk tech Pistons compared to proX ,Weisco, or others ? Did you do the rk head at the same time?

madmax · Dec 27, 2016

peaceofwork said:
Is their any thing special about the rk tech Pistons compared to proX ,Weisco, or others ? Did you do the rk head at the same time?

Pistons are a weisco made to RKT specs. If you buy a weisco Polaris 800 pistonit won't be the same. I did not do the RKT head, yet. If I do anything else yonit this year it'll be a 2.8 Camsno

Pro-8250 · Dec 27, 2016

Why does Indy Dan say that the new Polaris OEM pistons are the best on the market? Believe me, I am not a mechanic. Just curious.

mtncat1 · Dec 27, 2016

stock pistons is what indy dan likes to run on his set ups. the pistons rkt uses are lighter and stronger also fit much better than the stockers hence a noticeably smoother idle.if you want stockers the 13 and newer pistons are fine .

madmax · Dec 27, 2016

mtncat1 said:
stock pistons is what indy dan likes to run on his set ups. the pistons rkt uses are lighter and stronger also fit much better than the stockers hence a noticeably smoother idle.if you want stockers the 13 and newer pistons are fine .

What he said. I don't know what Indy dan recommends.

peaceofwork · Dec 28, 2016

Rktek runs 370 for a pair of Pistons what are stock Pistons for 13 and newer going for anyone know?
Normal weiscos or proX about 170 and spi cheaper yet.i am considering if rk is the smart move

Reg2view · Dec 28, 2016

RKT used to have Wosners made to his specs for his head, and also offered drop in replacements for the stock head. Two different designs. Ran a set in an 11 with his head and two dome sets. Ran well, 2 gr heavier in the primary with his pump premium head for the altitude, but about 5F hotter. Abit smoother. HP bump came from the head. Would have been more valuable with a TRS $28 thermostat fix to keep the timing from rolling back.

When I replace pistons for the stock head on a different pro I have, it will be the newer OEM 800ho's. Just proven, easier to find and get through any dealer, and not chasing anyone around on email or phone.

peaceofwork · Dec 28, 2016

well a quick call to the local guys who call them self's a dealership but stock nothing in parts they want- 289.00 canadian each piston , of course they will have to order them, and its going to be a week or so.
RKTEC - is looking a lot better than the stealership right now

ditch1000 · Dec 29, 2016

peaceofwork said:
well a quick call to the local guys who call them self's a dealership but stock nothing in parts they want- 289.00 canadian each piston , of course they will have to order them, and its going to be a week or so.
RKTEC - is looking a lot better than the stealership right now

I don't think you can go wrong with the RK TEK pistons and head!! I just got my sled out for the first ride yesterday; it is on year #5 of the Rev 1 drop in kit. This setup rips!! I have the 13.1:1 head and the kit that gives you 12 hp more... I run 2 more grams in the primary and at 5000' it revs to 8450 to 8550 rpms!! This sled really comes alive with the higher rpms!!!
If you go this route, you do need to do the $28 fix!! When I originally installed my RK TEK kit, the sled ran 135 to 140 degrees and the RPMs would fall back 7700 rpm and the sled would fall on it's face... This was right at the time when TRS came out with the $28 fix for the coolant bypass!! So I found the parts (get the heat shrink clamps; they look better than stock), installed the kit and the sled came alive!! The temps dropped down to 109-114 and the revs shot up to the 8450-8550 range!! Even in low spring snow; this setup will run 60 degrees cooler than a stock pro and the stock pro will shut down on overheating...
Also, as a side note, I have has the Polaris mechanics at the local dealership ask what was in the sled for engine work; they have said they have never seen a Polaris 800 run that smooth!!

madmax · Dec 30, 2016

ditch1000 said:
I don't think you can go wrong with the RK TEK pistons and head!! I just got my sled out for the first ride yesterday; it is on year #5 of the Rev 1 drop in kit. This setup rips!! I have the 13.1:1 head and the kit that gives you 12 hp more... I run 2 more grams in the primary and at 5000' it revs to 8450 to 8550 rpms!! This sled really comes alive with the higher rpms!!!
If you go this route, you do need to do the $28 fix!! When I originally installed my RK TEK kit, the sled ran 135 to 140 degrees and the RPMs would fall back 7700 rpm and the sled would fall on it's face... This was right at the time when TRS came out with the $28 fix for the coolant bypass!! So I found the parts (get the heat shrink clamps; they look better than stock), installed the kit and the sled came alive!! The temps dropped down to 109-114 and the revs shot up to the 8450-8550 range!! Even in low spring snow; this setup will run 60 degrees cooler than a stock pro and the stock pro will shut down on overheating...
Also, as a side note, I have has the Polaris mechanics at the local dealership ask what was in the sled for engine work; they have said they have never seen a Polaris 800 run that smooth!!

I had the exact same experience as you with my sled and the RKT pistons and 28$ thermostat. Good to hear. Very happy with the results

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RKT pistons and $28 thermostat

madmax

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