polaris 800cfi melt down with mbrp

[vinsonrmk]

I just had my 09 assault burn out both pistons on the exhaust side. my dealer is trying to tell me that it was caused by running a mbrp can. he said it reduces back pressure to much. i think he is full of crap. the sled has 850miles and most have been with this can. it blew on a -27c night and seemed to have lots of snow ingestion. dealer said this wouldnt cause it to burn up.
any thoughts?

 

[sled_guy]

Your dealer is clueless... not to say a can can't cause issues, but with the history of the 800 CFI motor to say that it is related to the can is just plain ignorant. Tell him that you will pay to have it fixed, put the stock can back on but that if it does it again he has to pay for the second one and reimburse you for the first one... you'll be getting your money back.

sled_guy

 

[Snoweasel]

I agree with Sled_guy. I have a MBRP can on my D7, it's been on since new. Sled now has 1700 miles on it and has run perfectly, no issues. I also have a D8 with an SLP can it has melted down 4 times now. Dealer warrantied all meltdowns knowing full well I'm running a can. It's not the can it's the engine with it's lean spots, excessive piston to wall clearances and head design. May be worth talking to another dealer.

Just my 0.02.

 

[polaris907]

Same issue

I had a 2009 800 Shift 144, while I owned it I had two major engine failures and one before I bought it from the dealer I was unaware of so three top ends all together in less then 744 miles. I complained and the dealer was amazing and traded me straight across for a 2010 800 RMK 155. I have had the 2010 two weekends and this past weekend while boondocking it blew up on me. The dealer mentioned something about my can but very little about the snow ingestion, luckily they are covering everything under warranty but I am in total agreement everyone else I talk to seems to think snow ingestion in the problem and the headlight adjustment know needs to be covered. My friends have the same sleds and this seems to be our only difference and they have no problems! Kind of silly to have a headlight adjustment know on a mountain sled anyways.

 

[R44guy]

The MBRP can is to loose and loses power when tested on the Dyno compared to the stock Polaris can. Under the right directions this may help possibly contribute to your engine failure when it comes down to fuel maps.

The only benefits of the MBRP can are the sound and the weight savings. Snow ingestion will also add to a possible failure but truthfully it is more likely the combination of two separate issues where the lean fuel maps and excessive piston to cylinder tolerances cause the majority of this kind of failure.

Obviously proper cold engine warm ups are still mandatory to protect your long term engine life. Obviously there are multiple repairs available such as the PCV, the Mountain Tek piston kit from pmspolaris, and maybe even the gizmo just based on all of the positive feed back on the forum.