1,700+ miles - 800 motor

[Dizzle]

Hey fellas I have a 17' 800 with an SLP pipe and can on it. Like the title says - it has just over 1,700 miles on it and the sled still rips and has given me zero issues.

My dilemma is do I put a top end in it this summer or would ya'll just keep riding it? Both cylinders read @ 105 psi @ 5k in elevation so it's not giving me any indication that she's getting tired, keeps me hanging with 850 Etecs, but I REALLY don't wanna get left on the mountain anywhere either.

I couldn't tell you if the oiler has been turned up or not. As far as I know it's completely factory other than the pipe and can. Thanks for any input

 

[kanedog]

Do the top end and then there are no worries. Go with your gut.

 

[volcano buster]

Any chance you can do a leak down test on it?

 

[Dizzle]

I think I might. Be a good piece of mind anyway.

Isn't "leak down" the same as a compression test?

 

[volcano buster]

No. A compression test accumulates the amount of pressure being built up with the movement of the piston/rings.
A leak down test measures the amount of pressure being lost around the rings (and valves if a 4 stroke). This allows you to calculate a % of loss. TRS said Polaris has modified their spec's as to when an engine needs a tear down.

I was able to run the input pressure up to 100 psi on mine and built a piston stopper to keep the non-tested piston at BDC.

 

[AdrenalineAddict]

I would recommend freshening up the top-end (Pistons) ASAP. I've had exactly 10 Polaris 800's (since 2011) lose the ring locating pin on the upper ring between 1,800 and 2,200 miles. I've always had warranty so I just rode them until they quit, but without warranty you're much better off spending roughly $850 for a new top-end versus $2,300 for pistons, cylinders, head, and possibly a crank ($1,200). A leak down test won't tell you if your pin is on the verge of ravaging your motor. A riding buddy of mine just had the same failure at 1750 miles a few weeks ago, and it appears parts are very hard to come by. My 2019 850 recently suffered the same fate at 2750 miles. My experience tells me that if you freshen up the top-end every 1,700 miles you may never be broke down..

 

[UP_CARP]

^^^^ this

Mine just did this at 1300 miles.

Also just did top end on another one with just shy of 2000 miles. Amazing how wallowed out the pistons were, caught that one before it was catastrophic

 

[MrIQR]

My 17’ blew the same compression at 3k miles, did a top end anyways. Was worried about the skirts not the rings. Right around 3,500 miles now, I personally wouldn’t do a top end yet but I that’s just me.

 

[Dizzle]

Thanks for all the input fellas I really appreciate it.

I'm gonna do the top end just as a preventative measure. Then maybe order a new sled in 24'

 

[Dizzle]

Quick update!

I rode it all last year and then took it into All Forms Motorsports in Idaho Falls this past summer. Dropped it off for a top end and got a phone call from them a few days later asking why it's there. I told them it was just for preventative measures and he said, "Well...I can do the top end, but I can't guarantee any performance OR reliability gains from it." He said I *might* gain a few points of compression, but I could possibly even LOSE a few points. He said that he'd run it and once it starts taking more than 2 pulls to start, then bring it back. He scoped the motor, he listened to it and said there was zero red flags coming up.

So that's what I did! I picked it up and I've been running it all season long and he's RIPPIN! Spent this weekend chasing my buddy on his Gen4 turbo and it takes me everywhere he goes. Continually amazes me. Currently @ 1943 and will probably have another compression test done soon.

 

[Massif master]

Riding East, so mostly tree riding, no prolonged Wide open runs like out West, 2020 RMK 800 with 4500 miles, compression 119-120, morning starts 2 pulls, 1 pull thereafter.

Dealer checked pistons via exhaust valves and said many more miles left...Never overheated, never coded for pre-ignition, stock clutches...I'm running it untill season's end, then top end next fall. Sounds good?