Rmk 800 blown engine issues

[Thedoityouselfguy]

I was looking for an rmk 800 for a back up sled but while searching on kijiji found that 95% of the pro rmks have rebuilt engines from 1200-2000 Kms. What's the deal? I know mnt tec has a good fix kit but do they last? Funny Polaris can still push production on these things without correcting the issue.

 

[dragonweld28]

The FIX Kit from MTNTK relsovles all the engine issues. And they last..... My cousin had his motor go down last year and he rebuilt it with that fix kit and put on 2200 kms problem free the rest of the year, More compression and power too.

 

[ABMax24]

I have the mtntek fix kit and 1200 trouble free kms so far, its worth the money.

 

[tex78]

So what happens to these 800 in the newer po po


I got 2700 km mountain on my xm first year, stock belt even

My 2010 xp has 3000 miles still all stock


Thought the newer po po after the dragons where better

 

[Wilk INStheWEST]

So what happens to these 800 in the newer po po


I got 2700 km mountain on my xm first year, stock belt even

My 2010 xp has 3000 miles still all stock


Thought the newer po po after the dragons where better

You've been around here enough to know exactly what is going on. Go trolling elsewhere.

 

[ABMax24]

So what happens to these 800 in the newer po po I got 2700 km mountain on my xm first year, stock belt even My 2010 xp has 3000 miles still all stock Thought the newer po po after the dragons where better

The pistons seem to shrink, not due to wear but the castings shrink increasing clearance causing piston slap and eventually breaking off the piston or cylinder skirt. The fix kits correct this with a better made piston as well as a longer skirt to spread out the side load. After a fix kit is installed the motors are significantly more reliable.

 

[AreWeThereYet]

Does this also happen with the older rmk 700's

 

[JMCX]

They got better with the Pro's in '11 but still not great. Then they made some changes for '13 and have been good since. It would be nice to see some real failure statistics from all the mfgrs but that will never happen. I have over 2000 miles on my '13 and the compression is the same as new. It's for sale too...

 

[JMCX]

Does this also happen with the older rmk 700's

The 700's have a stellar reputation.

 

[AreWeThereYet]

The 700's have a stellar reputation.

Good because I am ordering all my top end rebuild parts today/tomorrow.

I was looking at a newer 800 sled like the OP, but noticed way too many rebuild engines after so little mileage.

 

[ABMax24]

Does this also happen with the older rmk 700's

Yes and No, yes the piston skirts can break due to excessive piston to bore clearance but it usually due to wear from high mileage, not poor castings, at least that's how mine failed.

 

[tex78]

You've been around here enough to know exactly what is going on. Go trolling elsewhere.

No I'm serious.... Never paid attention

Was going to look at one for my kid, but mabe not now

The pistons seem to shrink, not due to wear but the castings shrink increasing clearance causing piston slap and eventually breaking off the piston or cylinder skirt. The fix kits correct this with a better made piston as well as a longer skirt to spread out the side load. After a fix kit is installed the motors are significantly more reliable.

Thanks for the info... Can't believe po po can't get there poop in a group...

That's the info I was looking for..

 

[ABMax24]

They got better with the Pro's in '11 but still not great. Then they made some changes for '13 and have been good since. It would be nice to see some real failure statistics from all the mfgrs but that will never happen. I have over 2000 miles on my '13 and the compression is the same as new. It's for sale too...

I bet if you pull apart the motor on your 13 you will see the piston to cylinder clearance is out of spec, the rings will still seal good making this issue hard to diagnose without actually getting inside it, that's why people are so worried about it, everything runs fine until the motor grenades. Polaris did thicken the cylinder skirts for 13 so they don't break as commonly but did nothing about the pistons.

 

[ABMax24]

No I'm serious.... Never paid attention

Was going to look at one for my kid, but mabe not now

Thanks for the info... Can't believe po po can't get there poop in a group...

That's the info I was looking for..

If you could find a good deal I would go for it, iirc the kits are about $700 plus a couple hours of your time to install and then you have a fresh top end, the 600's don't have these issues by the way if one comes up for sale.

 

[Wilk INStheWEST]

No I'm serious.... Never paid attention

Was going to look at one for my kid, but mabe not now

Thanks for the info... Can't believe po po can't get there poop in a group...

That's the info I was looking for..

Sorry Tex! If looking for one for you kid, grab one that already has a Fix Kit put in it, and it'll be a strong motor for ya. There are lots of them out there.

 

[Thedoityouselfguy]

Anyone get more miles on their stock engine from simply religiously letting it warm up before honking on the gas? I know that some performance Pistons are egg shaped and get round with heat which means that the tolerances won't be in spec until the engine is warmed up properly.......would this apply to the pro or is it more the jug that is the problem? Thanks for all the great replies.

 

[Wilk INStheWEST]

I religiously warmed up mine. But as said before, it is fine until it blows. So, I put in the fix kit this season hoping to avoid that. I'd rather put in the time and effort now (1200 miles), then wait and have to put in more money and down time mid season.

 

[polaris011]

I got got close to 4500 km out of my pro before it blew up and the reason she went was I was coming close to end of warranty and I let it get hot on the trail...I always warmed up before riding always good gas and always polaris oil .. I didn't think that wa all to bad

 

[cnelson6]

We have just over 2800 miles on my wife's pro on the original engine. We warm our sleds up for quite a while and I throw some oil in the tank. We are doing the fix kit on it as we speak.

 

[QMAO]

I have approx. 2200 miles on my pro and contemplating doing the RK Tek kit before it grenades and I have to replace cylinders,rods or crank.
Who and where in the central Alberta area handles the kit and able to do the install?