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2013 RMK Pro topend/compression/coolant/arrrrrr

B
Nov 28, 2016
19
10
3
Bozeman MT
I posted this over in HCS, but I realized I really use both of these for researching, so I thought maybe you guys over here might be able to help me out too

Thanks

New to the forum, I apologize in advance for the questions:

1. Bought a 2013 RMK Pro with 1200 miles, pulled the cord, felt like decent compression. Got it running (3rd pull from cold), let it warm up for a couple minutes, shifted into reverse and didn't hesitate a bit (good sign, I presume). Offered the $5800 and threw it on the truck. Felt pretty good. Drank a beer or 6

Get home, use my cheapo harbor freight compression tester. Take one plug out, replace with tester, hold throttle wide open, crank 5 times. Highest number 92psi (cold). that's at about 5,000 ft elevation. Other cylinder, 91psi (cold). Drank more beer...bought SLP topend kit.

Should I run it? I used the same tester on a 2005 m8 and got 125psi, which at my elevation was pretty much perfect. This one, not so great. But the cylinders are pretty much exactly the same psi, which is good...but that low?

2. On my topend, can I just lightly rub the cylinder walls using green scotch pad and wd40? After everything I've read, that sounds like the most reasonable prep.

3. When I got the sled home, there was no coolant in it. No leaks, no sweet smell, but no coolant in their (and I was watching the temp, never got it over 120F) So, I researched. The coolant cap seems like the cheapest, easiest first place. Then pressurizing the system to 10-12 psi and looking for leaks. Any other tricks?

4. Heard that SLP rings aren't as good as OEM. Then checked out how much OEM rings were...$146 for 4 rings? Maybe I missed something. Anyways, using the old ones seems like a bad idea. maybe I'm wrong.

Thanks everybody.
 

beamslayer

Well-known member
Premium Member
Nov 29, 2007
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Try a different tester to start with , Either look thru exhaust or get a bore scope and check condition of bore . I like the Mtntk top end kit the best , if you pull it down make sure to check cylinder skirts for cracks .
 

Murph

Polaris Moderator/ Polaris Ambassador/ Klim Amb.
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Respectfully, I disagree with 92 psi being normal @ 5000 feet.

All testers are different but I typically see 120psi @ 6000' on my Pro Ride Pros- We have four and I work on a lot of other Pros also.

No coolant in it at all????? that sounds really suspect. The temp sensor won't read air temp inside the cooling system very accurately, you definitely want to check the head for warping due to extreme heat.

Was there no coolant in the bottle when you opened the side panel? might need to check the water pump seal after being run completely dry.
 
B
Nov 28, 2016
19
10
3
Bozeman MT
Respectfully, I disagree with 92 psi being normal @ 5000 feet.

All testers are different but I typically see 120psi @ 6000' on my Pro Ride Pros- We have four and I work on a lot of other Pros also.

No coolant in it at all????? that sounds really suspect. The temp sensor won't read air temp inside the cooling system very accurately, you definitely want to check the head for warping due to extreme heat.

Was there no coolant in the bottle when you opened the side panel? might need to check the water pump seal after being run completely dry.

Yea, no coolant in the bottle, but I can't say whether or not there is any in the system. Hopefully it's just really low.

Isn't there some sensors that go off if you didn't have coolant? I ran the sled for about five minutes when taking it off the truck and nothing was beeping at me or lights flashing.

I think getting in there, topping it off with coolant and pressure testing it is the best bet. I've heard of people using bike pumps with those nozzles for filling balloons or whatever. What's the best place to hook it up? I was thinking the overflow tube, but wanted to make sure. Also 10-12 psi should be enough to initiate a leak, right?

Thanks again
 
F
Nov 26, 2007
113
30
28
www.boondockers.com
Use a different compression tester - from what I've seen/heard the gauge from Harbor Freight doesn't have a check valve at the tip of the hose that connects to the sparkplug hole (like most other testers have), therefore the volume of the hose becomes part of the cylinder volume which will lower the effective compression ratio and lower the reading a few psi. Also hold the throttle wide open and keep pulling until the gauge stops rising (usually after a few pulls). I would expect around 110-125 for a stock engine at that elevation.

Most radiator shops have a device that goes where the radiator cap attaches and that has a pump to check pressure if you can find a shop nearby.
 

SRXSRULE

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FWIW my 12 and 14 pros both checked at 105 PSI at 6200ft. Thats with BOTH spark plugs removed, throttle wide open, and 5-6 good pulls until it wont build anymore pressure. Mac tools, good quality gauge.

Try and barrow a better tester and re-check. Eric
 
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geo

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Dec 1, 2007
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Also,,, look at the oil pump adjuster ( 13's were still too "economical"). See if the paint mark is gone. The threaded portion should be pretty close to flush with the lock nut. Plus venting as you mentioned.

If this was done, and you followed Fastgas suggestions, and you get it to 110-115ish, your probably good to go. On a side note, a 05 M8 would be an aftermarket set up with probably a higher compression head so keep that in mind when comparing #'s on your gauge.
If not done, pull the pipe, scope pistons top to bottom through the y pipe for damage (scoring) no matter what the gauge says. Replace if scored and turn up the pump and go, if not scored turn up the pump and go.
Only place I've seen a '13 cylinder crack is from the back boost port straight down to the base cut out but the piston was way scored (meaning siezed at one point).

If you want to be really sure for the season (sucks to buy used but,,,) and the pump was not turned up, pop the primary (or just pull the bolt if you have a really good scope) and see if you have one of the last Mape cranks (there were not many in the RMK's though) or Fuji (part # on crank end).
If I got one with a Mape crank I would pull the throttle bodies and reeds and have a real good look (color and feel) at both big ends of the rods.

No doom and gloom here, just a bit from history and chances are history has already been taken care of.

If you want history on driveline and what to look for, start another thread after you drank a couple more beer and looked beyond the engine.
 
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sierraclimber

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Dec 14, 2009
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Oakhurst, CA (western sierra)
At 1,600 miles I felt a noticeable drop in power. Took the top end a part and the cylinder has a taper worn into it by .1000's. I had the oil pump turned up since I bought it new. Bikeman has a kit with taller, better made pistons I am going with. They have a taller gap between the rings and holes drilled in the side for more oiling. They can bore and replate the cylinder for you too if you need it. If your oil pump was not turned up and the sled was rode hard (possibly over heated too) it could be time for a new top end. http://bikemanperformance.com/snowmobile/polaris/rush-800/bmp-800-cfi-polaris-durability-kit.html
Best of luck. No one likes to buy a sled and then dump repair $ into it.

From Bikeman "For all Polaris 800 CFI & CFI HO motors, 2008-Up. The relatively short rods and pistons have been the cause of the short life of the stock pistons and rings. Most machines will lose 20-30 lbs of compression after just 1500 miles of riding which causes a loss in performance. How many miles do you have on your sled? If it has 1500 miles or more, you're in need of this kit! The key to this kit are the taller pistons we developed which allow less piston rock. This reduces the stress on the piston and rings dramatically. We also extended piston life by slightly changing the ring location, adding lubrication holes on all four corners of the piston, and Teflon coated the skirts. The Durability Kit includes a cylinder spacer that raises the cylinder the same amount as the piston is taller so port timing isn't changed. The added crankcase volume even produces 6 more horsepower so your engine life is extended dramatically while gaining power at the same time. The kit comes with two new Teflon coated pistons, rings, wristpins, circlips, longer cylinder bolts, our machined spacer, longer dowel pins, and two base gaskets. If you plan to keep your Polaris, you better get your Durability Kit shipped out today! 6 HP gain with no EFI Controller!"
 
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geo

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Dec 1, 2007
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" the cylinder has a taper worn into it by .1000'"

It's not possible to wear a 100 thou. taper into these things so it must have come this way. But, this has been discussed in history too. lol to the ol' guys here.
 

mtncat1

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Oct 19, 2008
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south jordan ut.
Respectfully, I disagree with 92 psi being normal @ 5000 feet.

All testers are different but I typically see 120psi @ 6000' on my Pro Ride Pros- We have four and I work on a lot of other Pros also.

No coolant in it at all????? that sounds really suspect. The temp sensor won't read air temp inside the cooling system very accurately, you definitely want to check the head for warping due to extreme heat.

Was there no coolant in the bottle when you opened the side panel? might need to check the water pump seal after being run completely dry.[he said that test was on a cold motor so it will be lower. my shop is at 4500' and i normally see around a 100 psi on pro 800s , my 800 with a 14 to head is barely 125 ,so i am surprised at what your readings are. but the gauge you use can make a lot of difference i have a snap on but it is made for automotive applications .
 

diamonddave

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Apr 5, 2006
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FWIW my 12 and 14 pros both checked at 105 PSI at 6200ft. Thats with BOTH spark plugs removed, throttle wide open, and 5-6 good pulls until it wont build anymore pressure. Mac tools, good quality gauge.

Try and barrow a better tester and re-check. Eric



My results are more in line with your findings and a few Polaris tech's.

I use a Snap-On Compression tester and at 324 feet above Sea-level, I always get 120-125lbs.

If Murph is seeing 120 psi at 6,000 feet then he either has head mods or aftermarket head on all the sleds he tests or his gauge is reading very high. Now if you install an 08-09 head, then I'd believe those numbers were real.

But...in all reality, I have seen some pretty F'd up 800 CFI's and have found compression tests to be normal.
 
B
Nov 28, 2016
19
10
3
Bozeman MT
So now there's this...

So last week i tried adding coolant and idling it and felt pretty good about where It ended up. I got the fluid to hold a proper level with getting up to temp.

Today, took it out for its inaugural cruise, only to hit 130 degrees on the first tiny hill. After letting it cool down, i got it up the hill then it got up to 130 again and was blowing smoke/burning off coolant. Popped it open to find the coolant hose running into the head leaking. Fixed that up, rode another 200 yards, it got hot again. I called it, got home and pulled the head. Nothing looked totally weird, but then i looked harder.

How the heck does coolant work its way up the oil lines!? It doesn't look like there was any coolant put into the reservoir. The engine sounded fine when i parked it so i hope i didn't do any lower end damage. But i do have a kit with all the gaskets for the top end, along with the pistons and rings.

Sled trip in 6 days...we shall see
 

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mtncat1

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south jordan ut.
i would pull that line and verify that it is coolant in the line , for coolant to get in that hose it would have to be pushed backwards through the crankcase , good luck
 

tuneman

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For starters, 130 degrees isn't hot at all. That's about normal in marginal snow. Now, if you hit 230 degrees, then you're getting hot. Anything under 200 isn't much to worry about.

Second, pull that oil line and check to see what's in there, as the previous post stated. If the previous owner used VES Gold oil, it can look green thru a tinted blue oil line. It's highly unlikely that antifreeze got in that line unless someone put coolant in the oil tank.
 
P
Mar 23, 2013
111
16
18
38
Choiceland sask
I could be wrong but im pretty sure the water pump is driven on the same shaft as the oilpump. If the seals are shot it could get coolant in the oil lines maybe? That could explain why the coolant is getting pressured up also because crankcase pressure can get back through the waterpump.
 
D

Drewd

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Feb 2, 2012
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www.imnotrightinthehead.com
I could be wrong but im pretty sure the water pump is driven on the same shaft as the oilpump. If the seals are shot it could get coolant in the oil lines maybe? That could explain why the coolant is getting pressured up also because crankcase pressure can get back through the waterpump.

BINGO, the water pump and oil pump are run on the shaft shaft and if the seal is run dry, it can leak. Previous poster stated that this could happen and it did.

I haven't looked on my Pro to see if you need to pull the engine to repair it but it would probably be easier to do so.
 

rydningen

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May 9, 2009
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Northern Norway
Yes, the shaft that runs the oil pump and water impeller is the same, but for coolant to find its way up the oil line would be a feat in itself!

The oring seal that is placed behind the impeller can fail, but the coolant that gets through here will run out a slot that is made in the pto center crank bearing seat, there is a separate oil line that goes into the space that holds the axle and brass gear on the crank, this oil normally goes out this slot into the PTO cylinder.

Coolant can in my opinion not travel up the oil line, it would end up in the cylinder instead, it might very well just be the color of the hose as stated above, but pull the oil tank and verify this.

My guess is that the leak from the hose on the head has been the culprit all along, if you had an substantial coolant leak through either a head oring or through the water pump seal and then into the cylinder, it would not have taken long for the coolant to wash of the oil film in your cylinder and cause scoring.

It is very hard to tell exactly what is going on without looking at the engine in person, but the wash on the head, and cylinders that appears to look good, (difficult to se) does not indicate a leak into the engine.

And as mentioned, an engine that sometimes hits 200degreees on days with poor cooling conditions is not unusual, but of course not ideal. The temps you were seing are normal.
 

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B
Nov 28, 2016
19
10
3
Bozeman MT
Rebuild

Here's where I'm at
-removed panel
-removed over structure
-removed steering linkage
-removed head
-took off oil tank...sure enough, the line is green, but it was pure VES going through it :face-icon-small-coo
-disengaged fuel rail from cylinder
-took out cylinders
-removed pistons and pins/rollers
-removed water pump
-
Now I'm just cleaning away. I can't believe the belly pan doesn't come off! What a pain to clean that area without removing the engine.

Anyways, power valves were gunky and the bellows were loaded with oil,so they got a good clean. Going through the cylinder inspecting and cleaning. I just cleaned up the cylinders with a green scotch pad and wd40. Seems to have brought back the crosshatching. Now i have to get the coolant out of the crankcase?? and give it a lube, then reassemble with new pistons/rings/gaskets. Here's how the pistons looked. Any tips or pointers going forward would be appreciated.

thanks
 

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