12 800 fix kit rebuild or return to stock?

Deangarth · Feb 24, 2017

I bought My 12 800 Polaris with a bike an fix kit installed. It burned down few weeks ago due to oil pump issues, (still sorting those out, looks like bad pump tho) but trying to decide to get the tall boy pistons from bikeman to rebuild it or take the jug spacer out and return it to stock piston height but still the bikeman or rktek pistons. I don't see reason for the taller piston and spacer on my 12. I know these helped the dragons but I thought the issue with pros was piston material... what is your guys thought? I'm trying to get her rebuilt and going, but don't want issues so if I haft a wait till I have more money so be it.

BILTIT · Feb 24, 2017

11/12 pro engines still need all they help they can get. Pistons were a big part of the problem.

I would get the same pistons you have in there and keep the jug spacer.

Deangarth · Feb 24, 2017

BILTIT said:
11/12 pro engines still need all they help they can get. Pistons were a big part of the problem.

I would get the same pistons you have in there and keep the jug spacer.

That's what I'm trying to figure out, keep the bikeman fix kit spacer and get the tall pistons, or get the same wossner pistons but stock night and remove the spacer. Didn't know if the 12 really needed the spacer

BILTIT · Feb 24, 2017

The spacer helps increase the case volume, very small positive but it all helps.

ripnit · Feb 24, 2017

IMO piston slop/rocking causes the cylinder skirts to break(11-12). Taller pistons help but need the spacer, RKTek claims his pistons are a tighter tolerances. But if you don't let the sled equalize the water temperature every time you start it you could cold seizes it.(should do this with any piston) I've ran both, have had better luck with the MTNTK fix kit.

Deangarth · Feb 25, 2017

Thanks guys.ill definitely get the taller pistons and leave the spacer. Look at mtn tk too

Deangarth · Feb 25, 2017

ripnit said:
IMO piston slop/rocking causes the cylinder skirts to break(11-12). Taller pistons help but need the spacer, RKTek claims his pistons are a tighter tolerances. But if you don't let the sled equalize the water temperature every time you start it you could cold seizes it.(should do this with any piston) I've ran both, have had better luck with the MTNTK fix kit.

Mtn tk uses wiesco Pistons, I'm liking the bikeman using wossner pistons.

Norway · Mar 2, 2017

Been lots of opinions on root cause of failure/low mileage wear. The fact that some just poor oil and gas and ride, while others replace pistons/jugs early leads me to believe that pistons and/or cylinders had poor quality control or just to loose specs.

So get pistons that have been out for a while. Mtntk has sold a lot it seems like. Polaris pistons were improved in 13 and again for 15, so get the 15 if you go OEM.

Now the important thing; Measure clearance! Get control of piston to cylinder clearance and ring end-gap!!
Also, if you have to replate after your burn down or replace cylinders, check chamfering of the ports so they don't kill your rings. And get help if you don't know how. It's only smart to know your limits, no shame (sent mine to Fastrax).

Cheers.

peaceofwork · Mar 5, 2017

Norway said:
So get pistons that have been out for a while. Mtntk has sold a lot it seems like. Polaris pistons were improved in 13 and again for 15, so get the 15 if you go OEM.

Now the important thing; Measure clearance! Get control of piston to cylinder clearance and ring end-gap!!
Also, if you have to replate after your burn down or replace cylinders, check chamfering of the ports so they don't kill your rings. And get help if you don't know how. It's only smart to know your limits, no shame (sent mine to Fastrax).

Cheers.

golden information right their, i studied quite a bit about potential problems and decided 15 or newer pistons if i went factory polaris and that i had to confirm no cracked cylinder tabs and yes i used a profesional to measure my pistons and cylindr

Turboegt · Mar 13, 2017

I've run RK Tek's, Bikeman's, and a standard set of 85mm Wisecos for the Artic Cat and a spacer.

So far the Wiseco for the Arctic Cat are holding up the best.

Put 200 miles on the Cat pistons and they are still sitting at 125psi on each cylinder.

RK Tek's were toast at 162 miles and Bikeman's were both toast at 250 miles.

RK Tek's went down due to a piston pin clearance problem.

Bikeman's went down for possible snow ingestion.

gtwitch · Mar 14, 2017

Good information here and I am currently building an 11 PRO and I would like to use Wossner with spacer plate but cannot find the part nunber for that application with the spacer plate, Anyone know this part number??
gtwitch in wyoming

peaceofwork · Mar 15, 2017

i used weisco,s i did not go the spacer plate route, 85MM and was care full to make sure i had 5 thou piston to cylinder clearance, its working really nicely .
i think you might pick up 2 HP using the spacer plate method because of increased crank case volume but its hard to prove DURABILITY... theirs lots of choices - good luck

Hansen13 · Mar 15, 2017

I'm running Mongoose Machine's fix kit, using the Wiseco pistons. I'm just over 1000 miles into the "fix kit" and am still getting 125psi both sides. Hear a lot of ups and downs of Wiseco pistons, but I've never had any issues with them. I also have my oiler turned up. Check and double check your clearances!

peaceofwork · Mar 16, 2017

what are you doing for a warm up procedure and restart delay before riding if you let it sit for a while mid ride ?
mid ride i never flash it up and head out, and i warm it up while i gear up then easy on the fuel the first mile, like not screaming the first 5 min.

Hansen13 · Mar 18, 2017

Yep best thing for the Wiseco pistons is good warmup procedures etc.. I think it's because they're made lighter and the expansion is a lot quicker or something like that. I've run them in 3 sleds now with no issues. We warm them up to temp getting ready, shut them down, then before we head out they warm up to operating temp. Then it's few easier miles before they get rode hard the rest of the day. We don't usually sit long enough for the sleds to cool down that much. Probably lots of different ways people do it, but this way works well for me.

Norway · Mar 19, 2017

peaceofwork said:
what are you doing for a warm up procedure and restart delay before riding if you let it sit for a while mid ride ?
mid ride i never flash it up and head out, and i warm it up while i gear up then easy on the fuel the first mile, like not screaming the first 5 min.

Yeah forgot about that. Put in TRS "$28 fix" in my cooling system, bypass T-stat from Doo. Lets it warm up/stabilize much quicker after sitting for a while. Engine is cooler at startup and rarely goes below 85F after startup before climbing again, never took of before it did.

RS

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12 800 fix kit rebuild or return to stock?

Deangarth

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BILTIT

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Deangarth

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BILTIT

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ripnit

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Deangarth

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Deangarth

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Norway

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peaceofwork

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Turboegt

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