Attn RMK owners: 2002 RMK 800 Won't rev. Help needed please.

[MRN]

I had bought this sled at haydays this fall and got it home, never rode it. Only Put a Hot seat single, Ypipe and Can on it. Rode it around and it only hit about 6800-7000 rpms. I figured clutching was bad so I ordered blue140-320rate slp primary spring, 50-34mtn cut helix, black/grey secondary spring, new buttons and spring in the middle hole.10-62's. As WinterBrew said for 6-9k. And 1080 polaris belt.

I figured if it works up at 6-9k it should overrev if anything down here where I am in MN. I rode it today with the new clutching at sealevel and its still only getting 7000 or so. I have 520N main jets and tried the needle in both #3 and #4 positions. I have cleaned the powervalves and have taken the springs out and tried it like that with no luck.

If I put the track up on a stand it will not rev past 7000. I took the belt off and revved it up thinking the machine might have a switch if the Temp Sensor on the head was bad it wouldn't let it rev out. However without the belt it revved right up easily past 7-8000. But when doing this I noticed the primary didn't look as if it was acting in a smooth movement but not sure. I am no primary expert or clutch expert so I don't know what to do but am guessing its still a clutching problem because it rips pretty good but then just hits the wall.

I am thinking either the wrong hole on the secondary or the primary is problematic.


I will take just about any Idea at this point clutching related or not. Anyone?

 

[XC700116]

Make sure you have clean carbs and GOOD GAS first!

I've seen motors only running on one cylinder get past 7000-8000 RPM with no load so that really doesn't say much.

got any buddies with a 700 that you could swap clutches with to try to diagnose? That would be easiest.

or

pull primary off and remove spring. and put the cover back on. now will the clutch move up and down freely but not sloppy? if not new bushings all around(full rebuild kit). If so remove cover and check the rollers in the spider. do the spin easily but not flop around? any flat spots on them? if so rebuild if they look good check your weights and pins. if all is good then start looking at the secondary, chaincase, jackshaft, and driveshaft bearings.

If you still cant find the problem start looking into the ignition system, temp sensors, tps sensor, pull plugs and look into cylinder with a light. easiest way to check is with exhaust off and pitson down, shine light up exhaust port and look to see if anything is wrong.

 

[TravRMK]

pull the powervalve covers off, and make sure there isn't any oily residue on the topside. If there is then the bellows need replaced. At any rate, make sure they are functioning well. BTW without the belt tha primary will just slam shut when reved, not very smoothly either.

 

[rmk8hundo]

Make sure you have clean carbs and GOOD GAS first!

I've seen motors only running on one cylinder get past 7000-8000 RPM with no load so that really doesn't say much.

I agree that is huge and many sleds will do exactly that. New gas, clean carbs, clean exhaust valves and check bellows, and try riding it because many sleds act like that on a stand but will be perfect and hit 8000 under a load. just my 2 cents. and if you are running it around forest lake or central MN I would try 64 or 66 gram weights because the 62's act somewhat like that in my 800 also.

 

[MRN]

I replaced the gas, cleaned the carbs, No Oil in the powervalve tops, good spark and have tried 10-64's with the same result.

I am going to try to find another primary to try.

Thank you
Any other ideas?

 

[jim]

If the primary was binding, it would over-rev. It should still hit rpms either way. Low rpms from the primary would mean it's shifting out too much too easily.
Hitting Rs with no load is easy either way. How to plugs look?

You also might have a CDI issue...it's pretty common on those sleds. They can give you a weak spark, and then when you load it the spark will not be strong enough and you won't get Rs. Could be as simple as a new spark plug too. Are you running resistor style? You have to run resistor style in Polaris or that can cause issues.

Jetting OK? Wash? Plug read? You might just be rich.

I'd also double check the powervalve....I've taken the spring out and forced them open in the past. Are they moving smoothly?

YOu should also look at your piston faces...if it was scuffed or seized in the past, that could be an issue as well.

Also...are you sure you are getting wide open in both carbs? Are the slides lifting all the way? You should try and check that...you might have a broken cable.

 

[Roadwarrior102]

temp Sensor!!!!!!!!

 

[winter brew]

A few things to loo for.....when you assembled the secondary did you preload the helix/spring 1/3 of a rotation? make sure by removing the belt and rotating the movable sheave....it should have significant resistance and spring right back, if it is sloppy feeling then it isn't properly preloaded.
Also..the jetting is HUGE! Possibly too huge to make any power. if the exhaust is the nly mod, then run 460's...these will be OK for down low at moderate temps....if you are going to do alot of WFO and it's real cold, then go up to 480's. Should be about 410's at 6-9000ft with the pipe.
Check the Ev bellows for leaking, oil will be visible.
Don't expect to get RPM on a stand, with no oad it upshifts too easy and holds RPM down...maybe apply a little brake for a couple seconds if that's you only option for testing.
Let us know what you find-

 

[XC700116]

Actually for that pipe at sea level the jetting seems about right. I thought holy Crap at first then I looked at what my SLP single should be at at sea level - 3000' and it calls for 540's and 560's in a 700

 

[MRN]

I am going to try to find a temp sensor when the dealership opens up. Because I am not sure the motor wasn't just freewheeling right past with out the belt on (similar to blowing a belt and hitting 9-10,000rpms).

I believe the secondary is preloaded correctly as it springs back about the same as before. Also I tried 390 mains in it for a couple rips to no avail so I went back. So don't think its Mains. ALso needle in #4 and #3 now.

Also I have field tested all of these senarios on my garage and on glare Ice out on the frozen pond.

I am convinced by JIM's line of thinking that its not the primary.

Heres what I will do........
1. 480mains
2. Temp Sensor (can I just plug in the wires on the new one and leave the old one in the head with the wires disconnected on the old sensor to test?)


Also could it be a throttle position sensor?

I am kind of in a bind to work on this for the week but I may just bring it with me and work on it outside.

 

[markoo]

Make sure you have the right pipe. It has to be for a VES engine if your sled is an 02. It's possible the pipe is for a 01.

 

[thefullmonte]

I think I would almost start by putting the ol stock pipe back on. Go back to what you know worked before and then go from there. Check the EV bellows for cracks or tears as was said earlier. Also, I'm not sure what EV spring you should be using at this altitude, but I bet its not the right one in there. 02 was jetted much differently than the 03 and later models. The stock nozzel and needle were never intended for flatland use.

 

[MRN]

Its not the powervalves. I have cleaned them, checked the springs, bellows etc. There would surely be oil on the top side if they had anykind of crack. This is my 3rd 2002 RMK and have had the hot seat single on a previous one and ran it perfectly down here with the same jetting. Does anyone know what rpm the temp sensor tells the motor to cut out at if its not working??

 

[jim]

Another thought...the thermostats go out on those on a regular basis. Is the head getting really hot?

I does kinda sounds like a temp sensor as well.

 

[winter brew]

One thing that concerns me here....you are testing on either the stand or on ice.....neither will load the engine and without a load it will not be even close to a good representation of RPM..ride it on some grass at least.
Be careful running it without a belt, NOT GOOD! I wouldn't do anything over a slow idle without a belt or it may get real expensive!
Do the 480's, double check the secondary preload and ride it on a surface that it can hook up on. I'm betting results will be diferent.
One other thing to check is a stuck choke plunger or cable.

 

[MRN]

Thanks, will do, I am getting the temp sensor tomorrow but won't be able to get home to try it until friday. Ill let ya know

 

[Joermk]

Check your motor mounts. Brother was having the same issue in a 01 and he had two broken motor mounts, causing the engine to twist and bind the belt.

 

[the 2x4]

I honestly think it is your primary. I would just try a round almond with some 58 or 60 gram polaris weights. Try that. Check your main jets and make sure they are clean. and needle position. make sure the connection to the temp sensor is good. if your temp sensor was bad it usually only makes it to 5000 rpms. if all else fails bypass the throttle position sensor see if thet helps. try not to rev it out without the belt. it might throw the crank off balance. That would make for a bad day. let me know what you find.

 

[MRN]

I picked up the temp sensor bypass kit from slp, and that made no difference. The motor mounts are not cracked or broken either.

Does anyone know how to check the Throttle Position sensor or how to bypass it to see if thats bad??? any help would be great, I am about ready to take it in somewhere.

 

[Roadwarrior102]

Unplug the TPS and the CDI will default to the max advance setting for the given RPM and Temp on the 3D timing map.