97 RMK runs on one cylinder til warm, then fires

[Gold5th]

Oh smarter and more experienced people than I...

I have a 97 RMK 700, it has twin SLP pipes, geared down, stock clutching.

This issue has been noticable since I went back to stock clutching, well more so.

Well.. ok..

Last year I had the clutching done, I had an almond square in it (came with the sled) but the clutch was engaging to high for here I was riding so I was constantly on and off the throttle to keep from hitting things like trees... so I had it clutched back to stock. Now it's had less than 20-30miles put on it since cause it drives me nuts.. I'll be riding, stop to cross a road or slow down turn and start to go up a hill, and it'll bog it'll rev to about 3500-4000rpm and sit there, it won't spin the track so I have to get off, hold the throttle and walk/push it where I want to go, once I get back to flat land it seems "normal" again.

Now in trying to figure out that issue I discovered another issue... I think they might be related. When I fire up the sled it only runs on one cylinder. the clutch side cylinder doesn't fire. Once it warms up a bit it'll start to spit and pop (actually blew the snow out from under the exhaust once and started a fire) then the other cylinder will kick in.

I tried new plugs.. helped for about 1 short ride. The plugs get pretty black pretty quick. Both plugs look identical.

So the yesterday I did a compression test.
75psi on the clutch side cylinder, 90 on the other - dead cold, hasn't been run all summer.
I started it, let it run long enough to kick in the second cylinder, then let it run for another 5min... no change, compression still the same.

So I have no idea.. I was thinking maybe the coil pack or whatever it is called on the sled.. but it's like my wife's car 1 pack for all cylinders, not like my truck 1 pack per cylinder.. so I was thinking that's probably not it.... as then both cylinders would have an issue.

The one cylinder fires pretty easy, after the first start of the year.

Any help would be great.

Thanks

 

[keefer]

Check for vacume leaks between the carbs and motor. Use WD-40 while it is running and spray arround carbs and rubber boots. possibly be the coil/spark plug wires.

 

[sled_guy]

I'm guessing the two things are not related. If you had the clutching changed back to stock, what did they do? If they changed weights or even helix then the belt tension/deflection or shim spacing could be off causing the bogging.

As for starting and running... the 97s were a cold blooded SoB that required some heat before they would run worth anything. Polaris put a thermostat in them in '98 for this exact reason. I'd check over that cylinder/plug/carb boot/reed and see if anything obvious shows up.

sled_guy

 

[Gold5th]

For the clutching they replaced the main spring, the weights, the pins, the buttons on the primary... on the secondary they say they cleaned it and tuned/whatever it.

I'm not good with carbs at all... I could try swapping the plug wires side to side, see if that makes a difference.

I have no idea if the reeds/jets are stock or not.. they wanted to charge me a few hundred $$ to figure that out...

Also if I'm at speed above 6000rpm and go up a hill typically if I don't let off the throttle it's fine, let off the throttle.. and I most like will have the bogging.

 

[X2Freeride]

I dont mean to point out the obvious but stock clutching with twin pipes isnt going to work its just plain wrong. Your not loading the motor correctly for the exhaust you have. Hence the big time bog your getting. If you have stock clutching you need to either go back to the original stock single pipe or clutch it correctly for the pipes you have. OEM stock sure isnt correct. I dont know what your elevation is other wise I could give you some advice.

With the compression that low and that big of a difference between the cylinders I would say your due for a rebuild. Your compression should at least be over 100 on each cylinder and no more that 5 psi different between the two. However that is saying you did your compression check correctly. what procedure did you use? Do you have the 220 cylinders or 824 cylinders?

First things first fix your clutching to run with the pipes that you have. Elevation makes a HUGE difference. From the sound of it your weights are WAY to light.

Here are the specs from SLP follow there recommendations for your elevation.

http://www.startinglineproducts.com/instsheets/09-710.pdf

 

[Gold5th]

Well I'm a newb, I've been riding for 2.5 years now.. I started with a 81 citation pos that my father in law was going to use for parts

Then I got the RMK....

I can wrench, but only with a fsm for other than basic basic stuff..

When i had the clutching done I was thinking of going back to the stock manifold and some sort of a can like a mrbp(sp?)... I find it way to loud with the twins...

I do kinda notice it being "slower" than before.. top speed has always been about 110km/h, it still is.. but when I first got it/took it out for the test rip 3/4 throttle from stop and it started to stand up... now on the best day I can pin it and just get up to top speed fast.

I was hoping this would be a quick/easy/cheap/any of the above fix as I was thinking about selling it as I don't ride it much. the wife doesn't ride and where I ride the ProX is much more fun.. the RMK as I said tops out at about 65-70mph on the proX I average about 75mph and top out at 95mph on the flats... plus it just handles better.

It looks like the motor was out fairly recently before I bought it.. when they put it back in they pinched the speedo cable.

For the compression test, I have a compression tester, I hooked it up.. had the ignition switch off, yanked the pull start cable 4 times. and watched the gauge to see if it went up at all with each pull... it didn't...

Elevation: 533 M (1,749 FT)

For the weights, I don't remember the number.. but they pulled out a polaris book and read off what stock was and put that on.. The weights that were on was 10-60 (The SLP pdf you linked says they should be 10-62 (So it looks like it was setup for 3000' to 5000'... which means the jetting may be off.. based on that pdf as well)

The current spring is a blue with a white stripe, almond square was on there

By the numbers on the side of the cylinder sleeve, I'm guessing 824 (5121824)

 

[X2Freeride]

Now did you check your compression after it had ran or was this a cold check? Also did you hold the throttle wide open when you did the check? your cylinders are indeed 824 cylinders. But being as this is a 97 I would guess this has been rebuild before. As far as I know most 97's came with 220 cylinders. So who knows if the rebuild was done correctly. Your compression should have much higher than it was. 90 is bad, 75 is really bad. Like I said there shouldnt be much of a difference between the two. Absolutely no more than 5psi.

As for your clutching, just like I said its completely wrong for twin pipes. I dont know why the dealership or whatever didnt tell you that when they switched it out for you. If you go back to the stock pipe and whatever can, on the 97 and 98's the stock can was just as good or better than any after market job, as it was about as light as you can get stock, you will be just fine and the sled is going to run MUCH MUCH better.

This is where your bog is coming from. It still doesnt explain that low compression problem you have though. Still change out your exhaust or have the clutching changed to what is correct first. From there see how it works and then address the compression issue if the problem persists.

 

[Gold5th]

Yes, I did the compression test dead cold, ran it for 5min, about then the other cylinder started to fire, which is wierd.. cause normally it fires sooner and pops and crackles when it does start to fire.. this time it just turned on and the idle got smoother.

Then I let it idle for about 5 min blipping hte throttle here and there, then I shut it off and did the compression test again without letting it cool down.

Bugger.. I wonder why compression is so low... heh I saw a 754 overbore piston kit on e-bay for cheap

 

[Stroker Customs]

Sounds to me like you have a basket case going on here. I would start with some jetting sounds like this sled is pig rich and won't even idle. I would try and open up the pilot air screw to give it more air to see if you should change out your pilot jets chances are if this came from a higher elevation area than you will have to change pilot jets needles and main jets. Again this is just an observation from what you said because you said that the plugs are black and full of chit. Get motor jetted where it should be then check compression then once you have motor where it should be then dial in clutching. It does no good to setup clutching around a low end bog problem however clutching can cause bogging so you kinda need to know what you are doing but look at the plugs and get the thing to idle on both cylinders first that's my opinion

 

[Stroker Customs]

I do agree though your clutching is way off if it has twin pipes

 

[Gold5th]

It only started the low end bog after I had the clutching done.

It does start and idle no problems.. ok other than for the first minute or so it only runs on one cylinder

But yeah, it could be running way rich.. the plugs were a little "wet" when I pulled them out to do the hot compression test.

oddly enough my snowblower is running so rich it won't rev up heh (but I just got it used)

Now could it be it's 20 Degree Celcius plus right now... and I normally ride at well -5 down to -45....

 

[sled_guy]

Find a different shop and have them work over your clutches. They were completely apart if the buttons were done. Even if the right setup was put in it, which it sounds like it wasn't, they may well have reassembled them wrong which would not surprise me if they put a stock setup in a piped sled.

Peak in at the drive clutch (front clutch) and sled the belt all the way to one side. Then measure how much clearance there is between the belt and the other side of the clutch.

sled_guy

 

[Gold5th]

I actually know the guy who did the work, he's normally really good at it. I explained what I wanted, for the clutch to fully engage at lower RPMs and they just did it... maybe they thought I had a clue heh.. I'll see if I can do the measurement you said tonight when I get home....

Get the clutches done again.. ugh... that was $500 last time...

I have all the parts they took out in a bag... the old pins, buttons, wieghs, spring... maybe I should have them put the old weights and spring back in...

 

[Gold5th]

So I "measured" I'd say about 3/16" space.. I can get my truck key in the gap and have about a 1/16" left.

 

[X2Freeride]

Another symptom of the running on one cylinder could maybe be an issue with the plug wires/ the coil/ or the stator. Try checking the plug wires to make sure they are still good. Have the dealer check the stator.

I seem to remember on my 98 when the stator was going bad it liked to run on one cylinder on warmup.

 

[Gold5th]

I'll ask them about that... is there an easy way to test it? or not really?

 

[sled_guy]

So I "measured" I'd say about 3/16" space.. I can get my truck key in the gap and have about a 1/16" left.

Ok, that's a lot. I understand the shop may be good at what they do. Is the belt a new belt on there? With 3/16" clearance you are starting out in a higher gear when it engages and if the machine is down on power (low compression would suggest that) then it will bog.

When a clutch is put back together after replacing the buttons you have to be careful to make sure the spider spacers fall in to the groove. I've seen it happen lots of times where they hung up and caused the gab to be too wide. In fact, years ago when Max Maxedon who runs Tri-City Polaris in Centerville was running Swains in Salt Lake he would fire a mechanic if they ever made that mistake.

Regardless, you are fighting a couple of issues. Finding someone to go through those clutches and make sure they are exactly right is going to make a big difference on performance and will likely make a difference on the life of the motor.

Where are you located?

sled_guy

 

[Gold5th]

Ahh I see heh..

I'm up in Northern Alberta Canada