1900 miles, rebuild?

Iowa__Freeriders · Dec 1, 2016

I have a 2013 pro rmk 800, PAR Head, MDS clutching, oil pump up 1/2 turn and a can rest is stock. 1900ish miles trouble free for the last owner and myself. did compression check last year end of season and was within spec. asking around and my riding buddies say ride it till she blows, tech says rebuild (I would use some sort of kit, MTNKT, bmp) I like the idea of rebuilding as a peace of mind when I drive 12+ hours to the mtns. but also don't want to be wasting money if the sled would still last me a whole season or 2 more. I don't ride it in iowa, strictly use it for Wyoming trips usually 2-4 trips a year depending if I get time. might be a dumb question but haven't had a sled with this amount of miles for awhile. thanks!

AdrenalineAddict · Dec 1, 2016

Personally I would remove exhaust valves, give the pistons a look. Provided there is not any signs of scuffing I'd reassemble and run it. Some of the 12's required a piston change every 1,800 to 2,000, I am not sure if this was a metallurgical issue or not. I know of a couple 13's and 14's that have gone beyond 3,000 miles without any piston issues.

Drewd · Dec 1, 2016

New pistons and rings aren't terribly expensive and cheaper then if a piston skirt breaks and does more damage.

Pro-8250 · Dec 3, 2016

We are debating the same issue. 2013 800 155"with 2700 miles. Oil pump turned up 3 times since we bought it new. I just talked to a Polaris dealer service manager and he said Polaris recommends doing the top end at 2000 miles. He also told me he and his buddies go with Indy Dan on their sleds.

diamonddave · Dec 3, 2016

Guys.....do yourself a big favor and install the MTNTK Fix kit. These Pistons just collapse and create such large piston to cylinder clearance and ring wear is so accelerated in the 800CFI-2.

I'd be shocked with your current mileage if you already not at least 0.008" probably more and your rings aren't wasted.

Pro-8250 · Dec 5, 2016

Not trying to hijack the thread I just didn't want to start a new one with the same questions.
Diamond Dave. I thought I saw on Indy Dan's web site that he said Polaris piston's are the best out there. My kid is thinking buying OEM pistons, rings, and gaskets. Would that be better or worse than the MNTK. I am not arguing or being a smart asss. I haven't messed with two stroke engines and know very little. In the end the decision is up to my kid. Thanks in advance for the info Dave, and you too! PPK for the thread. :face-icon-small-coo

Sage Crusher · Dec 5, 2016

Correct me if I am wrong- but didn't the 13-15 pros have better pistons and this problem didn't go away, but was GREATLY reduced in the number of failures?
With the mileage you have Polaris_Powder_King. I would be pulling it down anyway,especially if your planning on keeping it another year or 2 as you had indicated.

Iowa__Freeriders · Dec 6, 2016

Taking all of the information into consideration! its going into the shop this week, see if the pistons are worn even slightly and go from there. if i put a new top end kit in i would also be buying power commander+ Auto Tune just to be safe with the PAR head clutching, stock programming etc. previous owner ran 70%/30% - 91/100LL don't know if that wears an engine down more?

Dave64 · Dec 9, 2016

Cylinders

I pulled my 11 apart with about 2000 miles, It was hard to see but I did have a crack on the intake side of the cylinder, make sure you look them over very closely, may save a case and a crank in the future.

the fix-it guy · Dec 11, 2016

If a piston fails... it will most likely punch a hole in the bottom case. Not a quick and easy fix nor cheap. I would do pistons or a fix kit.

RoostinRyan · Dec 13, 2016

I pulled my 12 apart and rebuilt this summer. I was noticing some issues when I was riding last year. Bogging, dying when switching to reverse, etc. When pulled apart I was astonished the thing even ran as there was so much piston to cylinder wall clearance. It had 1800 miles on it and was making 107# and 103# on each cylinder. Now it's making 137# each side with the par head. Runs way better and pistons were cheap.

sledhed · Dec 13, 2016

Dave64 said:
I pulled my 11 apart with about 2000 miles, It was hard to see but I did have a crack on the intake side of the cylinder, make sure you look them over very closely, may save a case and a crank in the future.

11's and 12's were worse for this, thinner cylinder skirts, I suspect 13 and newer are not immune but much less likely to have this happen.

Also you could inspect through the exhaust ports and have everything appear normal but still have enough piston clearance to be worth rebuilding. As others have stated here, top end is much cheaper than throwing a piston skirt or cylinder skirt through the bottom case... then you basically end up buying a complete motor, lots of money there...

Iowa__Freeriders · Dec 19, 2016

Decided to do the top end and will be ordering a kit soon. question I have though is a kit with the spacer going to cause problems when running my PAR Head?

peaceofwork · Dec 26, 2016

Same situation

I have a 2012 pro 3900 miles, I don't know the history of it but it runs strong and no chattering or piston slap, by looking at it I don't see a spacer plate or any indication the head bolts have been removed ever . I'm very concerned almost scared to run it compression is good but I know in my heart I better do something .
I don't want to mess with everything but I wonder about logical order of progression...
Should I pull it down and inspect cylinders and make a decision of new Pistons only ? I think about proX
Might do weisco's
I heard of spi
What's working good for guys that skip the kit and just install new Pistons?
Is a fix kit /durability kit really an improvement over just new fitted Pistons?
What Kitts are not making people happy and what's working good?
Finally are their any good movies of a re and re posted?

Iowa__Freeriders · Jan 4, 2017

I went with the RKT pistons and Vforce reeds, hope to have a trouble free season!

Merlin · Jan 4, 2017

Good morning,

New pistons are only as good as the bore they are being installed in.

The piston to cylinder wall clearance should be measured & if found to be not within spec. the cylinder will need to be re-plated & re-sized accordingly.

Don't skip this step or you may very well be wasting your time & money on the overhaul.

polaris_powder_king said:
I went with the RKT pistons and Vforce reeds, hope to have a trouble free season!

Iowa__Freeriders · Jan 13, 2017

Merlin said:
Good morning,

New pistons are only as good as the bore they are being installed in.

The piston to cylinder wall clearance should be measured & if found to be not within spec. the cylinder will need to be re-plated & re-sized accordingly.

Don't skip this step or you may very well be wasting your time & money on the overhaul.

I agree and the shop will be checking all specs to be sure, having a local shop do the work for piece of mind. Should be done this week!

sierraclimber · Jan 13, 2017

Noticed a loss of power on my 13 at 2,000 miles. 13.5 head and can.
Just finished doing the Bikeman durability kit and adding v force reeds. Bikeman diamond honed the cylinders. Their pistons are very good and longer which addresses some of the problems with the stock pistons!
Really woke up the power and more peace of mind not worrying about when the pistons are going to fail.

Iowa__Freeriders · Jan 13, 2017

sierraclimber said:
Noticed a loss of power on my 13 at 2,000 miles. 13.5 head and can.
Just finished doing the Bikeman durability kit and adding v force reeds. Bikeman diamond honed the cylinders. Their pistons are very good and longer which addresses some of the problems with the stock pistons!
Really woke up the power and more peace of mind not worrying about when the pistons are going to fail.

are you running a power commander or some sort of controller with that?

RJF · Jan 14, 2017

I just picked up a 13 Pro 155 with 1550 miles on it. It runs identical to my 14 Assault that only has 300 miles on it. I don't think I am going to do anything with it for another 500-1000 miles.

Only thing I noticed different was on the trail at 6,000 ft, it would tach out at 8400rpm. My Assault won't go above 8250. Supposedly this Pro is bone stock.

1900 miles, rebuild?

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