Mtntk fix kit?

[SU27]

I do RFM

You can run any oil you want... It's just his any many others opinion not to run synthetic in any 2s... In fact its probably the only thing him and Indy Dan wouldn't get into a pissing match about. lol

Paragraph 9 of "RK Tek 858 Polaris REV-2 CFI Big Bore and Drop In Kit Installation" :

9. Install Head. Torque @ 22ft/lbs<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
a. PREMIX a 150:1 oil ratio in 1<SUP>st</SUP> tank of fuel. RKT recommends to always pre-mix at 150:1 in addition to your oil injection system. NEVER run ANY synthetic oil in this engine.<o></o>

 

[Reg2view]

Kelsey does have a big one for synth oil. Lots of people have run them successfully with either, FWIW. Run good oil, run enough of it. Corrosion-wise, in high moisture environments, dino oil does make more sense.

The only thing he and Indy Dan agree on - that's a good one! Not posting on the Snowest Pro forum might be the other.

 

[Braaap12]

Has anyone ever tried this set up? https://www.mtntkperformance.com/engine-performance/drop-kit

 

[IQRIDR]

Fix kit works great but a lot of them that go down, are from not having the ring gaps adjusted correctly, ESPECIALLY on a new (or replated) cylinder. If the ring end gap is not at the very least .020, the motor will not live regardless of conditions or warmup procedure. We rebuild a lot of them that go down from this, the usual way you can tell is vertical scoring lines with small gaps horizontally between them- this is from the ring ends butting together with the top end gets hot.

I build them based on how I think a customer is going to use them. If I think a guy is really hard on his machine, I will bring them all the way up to .022-.025 ring gap. Usually slightly looser on the bottom ring that the top, I like to split them .020-022 top, .022-025 bottom. We have a very stringent heat-cycling, warmup, and breakin procedure, and if they are all followed correctly, the failure rate is probably 2% over 1000 miles. That's as good as it gets.

Anyway not a lot of professionals willing to share that info since we make our buck fixing other people's mess-ups, but there it is.

 

[rmscustom]

Fix kit works great but a lot of them that go down, are from not having the ring gaps adjusted correctly, ESPECIALLY on a new (or replated) cylinder. If the ring end gap is not at the very least .020, the motor will not live regardless of conditions or warmup procedure. We rebuild a lot of them that go down from this, the usual way you can tell is vertical scoring lines with small gaps horizontally between them- this is from the ring ends butting together with the top end gets hot.

I build them based on how I think a customer is going to use them. If I think a guy is really hard on his machine, I will bring them all the way up to .022-.025 ring gap. Usually slightly looser on the bottom ring that the top, I like to split them .020-022 top, .022-025 bottom. We have a very stringent heat-cycling, warmup, and breakin procedure, and if they are all followed correctly, the failure rate is probably 2% over 1000 miles. That's as good as it gets.

Anyway not a lot of professionals willing to share that info since we make our buck fixing other people's mess-ups, but there it is.

Great advice... The kit I installed last year the ring gap was .015" starting out in stock cylinders. If I would of run it like that I probably could of come on here and told you what a POS it was after a few miles.

 

[IQRIDR]

Yep .014 to .017 is how most of them are before adjustment and they will seize without a doubt in this area. Lot of guys will have bottom end problems from the rods still trying to turn a piston in the bore that is trying to weld itself to the nicasil. Proper technique is the difference between a runner and a flintstoner!

 

[die hard poo]

Fix kit works great but a lot of them that go down, are from not having the ring gaps adjusted correctly, ESPECIALLY on a new (or replated) cylinder. If the ring end gap is not at the very least .020, the motor will not live regardless of conditions or warmup procedure. We rebuild a lot of them that go down from this, the usual way you can tell is vertical scoring lines with small gaps horizontally between them- this is from the ring ends butting together with the top end gets hot.

I build them based on how I think a customer is going to use them. If I think a guy is really hard on his machine, I will bring them all the way up to .022-.025 ring gap. Usually slightly looser on the bottom ring that the top, I like to split them .020-022 top, .022-025 bottom. We have a very stringent heat-cycling, warmup, and breakin procedure, and if they are all followed correctly, the failure rate is probably 2% over 1000 miles. That's as good as it gets.

Anyway not a lot of professionals willing to share that info since we make our buck fixing other people's mess-ups, but there it is.

You are probably right Chad on the two seizures from my install on the ring gap. I didn't do the ring gap adjustment/verification. So it could have been the culprit. Definitely had the vertical scoring line all the way around the cylinder wall. Thanks for the tid bit of info! I will use that information in the future. Looks way easy to do too.

 

[IQRIDR]

You are probably right Chad on the two seizures from my install on the ring gap. I didn't do the ring gap adjustment/verification. So it could have been the culprit. Definitely had the vertical scoring line all the way around the cylinder wall. Thanks for the tid bit of info! I will use that information in the future. Looks way easy to do too.

Yeah definitely. Real easy to do, just make sure you only file in ONE direction, then use some emery cloth or fine sandpaper to smooth the edges of the ring end.

 

[djk2018]

the truth

so after a few years what has been the overall outcome?

 

[Dogmeat]

I just installed one of the MTNTK kits in a 2014 Pro 800 that had grenaded itself last season ...

The bottom end, cylinder and head were all repaired by SLP .... Anyways, got it all put back together and everything started up just fine, pre-mixed 60:1 in the tank for break-in, etc ... Did 3 or 4 heat soaks on the engine in the garage.

Got the sled out for the first time yesterday and everything seemed to be doing just fine, the sled would tac out at 8100 rpm WOT down the trail, etc .... When I got the sled in deeper snow, it was losing RPM pretty bad though. I climbed one hill with it and the motor was literally bogging down, not powering out and I was only pulling 7400-7600 RPM ...

Could this somehow be a fuel issue? The only thing I can possibly think of that I didn't get right is the inner injector o-rings. Its [possible that I may have installed them backwards, but would that cause the motor to bog like that? I'm gonna try getting the sled out one more time before tearing back into it, but it doesn't seem to me like it should be losing power in the deeper snow like that on a 100% fresh motor.

 

[Octanee]

I just installed one of the MTNTK kits in a 2014 Pro 800 that had grenaded itself last season ...

The bottom end, cylinder and head were all repaired by SLP .... Anyways, got it all put back together and everything started up just fine, pre-mixed 60:1 in the tank for break-in, etc ... Did 3 or 4 heat soaks on the engine in the garage.

Got the sled out for the first time yesterday and everything seemed to be doing just fine, the sled would tac out at 8100 rpm WOT down the trail, etc .... When I got the sled in deeper snow, it was losing RPM pretty bad though. I climbed one hill with it and the motor was literally bogging down, not powering out and I was only pulling 7400-7600 RPM ...

Could this somehow be a fuel issue? The only thing I can possibly think of that I didn't get right is the inner injector o-rings. Its [possible that I may have installed them backwards, but would that cause the motor to bog like that? I'm gonna try getting the sled out one more time before tearing back into it, but it doesn't seem to me like it should be losing power in the deeper snow like that on a 100% fresh motor.

how's it feel down the trail power wise? Loosing rpm, had an old sled do that and it was clutching. springs get weak over time, etc etc, maybe coincidental to engine work?

If it was loosing fuel you'd be setting the DET code for sure as it'd be leaning out, especially considering the throttle bodies would be wide open letting in all the air so if it never fueled for it...

Injector o rings leaking would cause a high idle I'd bet being that its a vacuum leak.


Did you set your ring gap? turn up your oil pump?

Also others may argue otherwise, but putting oil in your fuel to a small degree leans out the fuel, and I can't see it really being beneficial to the sled as the injectors inject as the piston comes down, basically just puts oil on top of the piston to be burned. best to turn up the oil pump which makes everything happier.

 

[sledheadd]

so after a few years what has been the overall outcome?

That sled is still running those wiesco pistons.
When i installed the fix kit we also did some porting so i can't really comment on any performance gains.
That sled is my wife's sled now and has about 1200 miles on it. 165hp @ 2200' running 100ll
i never move the sled until temps are over 110. IMHO warm up is essential for these pistons to live a long life.

 

[Dogmeat]

how's it feel down the trail power wise? Loosing rpm, had an old sled do that and it was clutching. springs get weak over time, etc etc, maybe coincidental to engine work?

If it was loosing fuel you'd be setting the DET code for sure as it'd be leaning out, especially considering the throttle bodies would be wide open letting in all the air so if it never fueled for it...

Sled is tac'ing out right at 8100 WOT on the trails, right where it should be.

Injector o rings leaking would cause a high idle I'd bet being that its a vacuum leak.


Did you set your ring gap? turn up your oil pump?

It was idling right around 1800 rpm ... should be good there. I did check the ring gap, and from what I remember it was right on the bare edge of the tight spec, but within spec.....tight, but within spec. I did turn the oil pump up.

Also others may argue otherwise, but putting oil in your fuel to a small degree leans out the fuel, and I can't see it really being beneficial to the sled as the injectors inject as the piston comes down, basically just puts oil on top of the piston to be burned. best to turn up the oil pump which makes everything happier.

I'll try to get the sled out this week again to double check, we put 4 fresh gallons of 91 non-eth in it after riding it ... That may be a a good idea to just drain whatever is in the tankk right now and start fresh without premix. It was using oil as of the last ride just fine.

 

[diamonddave]

I would highly recommend replacing the fuel filter.

S/B done every season and every rebuild. They restrict very easily due to their internal design.

Also, your low RPM "might be" from the extra pre-mix (always recommend). 60:1 pre-mix in the tank is pretty aggressive. Normally go with 100:1.

This could be partially fouling the plug(s) in the off trail, deep snow type of engine and clutching loads.




And pre-mix does not cause an air/fuel mixture to become more lean. Period.


Oil does not magically become "air" once it's mixed with fuel.