Clutch Weights and Spring

7danie49 · Nov 23, 2015

Hello everybody, I'm new to this forum and rather new to snowmobiling in general. I have picked up a 05' rmk 900 from a family friend that rode it at sea level. I have spent some time looking through this forum and others, but haven't found what I'm looking for.

So I know this is a problem sled, but it seems to be a good one as it has been running great for my friend through the years. With that being said, I'm taking my chances by not doing the 50 or so fixes to make it 'reliable.' However, I will be using this sled at 9,000 - 12,500 or so feet of elevation for which I've been told I need clutch weights and a different spring.

I have tried to order them through my local dealer twice, but they haven't looked up the ones I needed or contacted me back. I have also been advised to get adjustable clutch weights in case I change elevation ranges and whatnot.

So my question is, what clutch weight and spring do I need for a stock rmk 900? And do I need anything else?

Thanks,
Daniel

guidoxpress · Nov 24, 2015

This is the clutching I would get, u can order it all from SLP directly.

Primary spring.....SLP blue/pink OR green/pink (depends what rpm u want to take off in, the green is higher rpm)
Primary weights u can get factory 10-68 and 10-70s and play with them or get the SLP 74g MTX adjustable weights

Secondary spring I would get the team black/white and 1 derlin washer

I would get a good helix as well but all over eBay cheap

Make sure your belt is in good shape and u have the belt deflection set correctly.

Good luck. And welcome aboard

Sent from my iPhone using Tapatalk

7danie49 · Nov 28, 2015

Hey guidoxpress,

Thanks for your reply and help. I really appreciate it. Excuse my ignorance, but I have a few more questions if you wouldn't mind.

1. The first is concerning the primary spring. Is there an advantage to starting off at a higher rpm? What is the cost of this advantage? Is it a big advantage or does it not really matter?

2. So I found the 10-68 and 10-70 weights on ebay for $40 bucks cheaper together than the adjustable slp ones. Will the adjustable weights cover more range? Do I need more range? As I don't know all that much about sleds, I'd rather not have to mess around adjusting things too much. Taking this in account, which would you recommend?

3. To clarify on the secondary spring, strictly the black and white? Some of them are black/white/another color. And any idea if the 900 spring cup is fixed or floating? The directions to install the delrin washer vary depending.

4. What kind of helix should I be getting? Obviously one for a rmk 900, but what do you mean by 'good'? Like aftermarket brand or what? Any recommendations?

By the way, the sled and I are both from Anchorage, but I'm going to school down in Colorado so it's coming down to join me. Thanks again for the help.

guidoxpress · Nov 28, 2015

No worries man. Ask away .

1. Starting off in a higher rpm depends on ur style of riding. I don't care for it because u will trench harder once ur clutches engage using a higher engagement. The finish rate of the spring affects final shift out. So u will wanna stay around these ones. Which I forgot to include the one I use lol.
From lower engagement to higher.
A. Black/Pink (my favorite)
B. Blue/Pink
C. Green/Pink

2. The problem with not getting adjustable weights, is if u use the 68g weights and it over revs, u have to buy another heavier weight.. So u will save money in the long run with adjustable. Just note the MTX weights run 4g heavier then stock..so if u use 70g stock, u buy 74g mtx weights.

3. Stictky get the "team black/white" is literally the perfect one for the 900.
The derlin washer is super easy to install. Only need 1 between the spring cup and inner sheave. The cup "floats"

4. U will need a TSS-98 team helix (8 bolt).
Make sure it has ER at the end of the number meaning (electronic reverse). Ideally find a helix that has a starting number from 58 to 66 (anything in between is fine), second number should be 42 or 44 or 46 and final number of 44 or 46
So it should be like this. 58-44-46ER
These tss98 helix will be in the Polaris and skidoo models so lots of them for sale on eBay too

Sent from my iPhone using Tapatalk

7danie49 · Nov 29, 2015

Alright then, a few more things.

1. What elevation will the 74g MTX adjustable weights cover? What gram range (of fixed wights) will the adjustable weights cover? And is there some sort of chart to look at for weights according to altitude? Do I need a rivet tool to adjust the weight?

2. How do I know if the sled is over-revving?

3. Is there an optimal helix I should be looking for? I have found a couple on ebay that meet the requirements. Or does it not really matter and any of them will do the trick? I'm leaning towards a 62-46-46-ER that I found, will this do the job?

Thanks again!

guidoxpress · Nov 29, 2015

Here's a link to download the service manual.
http://www.mediafire.com/?tx80y945oiec7mm

1. The mtx weights require rivots and a tool to remove them on the fly, if u don't wanna mess with it. Stick with 10-68 weights, which is what polaris calls for 8-10k ft. Don't have access to clutch chart but Google, refer in here or look in the service manual link.

2. Again, look in the forum. Over-revving is around 8100-8300rpm I think... But stock or modded with the 900. U will be lucky to get above 7800rpm really. So stick around this 7800.

3. For longer tracks u want a lower helix (1st number) to prevent trenching. 58 is ideal, however a "normal" rider will never tell the difference in a 58 vs 62 ect. The imp part is the middle and end. And a 46 for both of these is perfect. I say snag it now.

Do some reading man. All this info is covered in the 900 section. U will tend to see less help on here with common question cause they view new ppl "lazy" for not searching

Hope that helps

Sent from my iPhone using Tapatalk

7danie49 · Nov 30, 2015

I hear you guido, it's just hard to look through all of this information when I don't really know anything about sleds and often times the information is for a slightly different application which I don't have the knowledge to tell if it will make a big deal or not. With that being said, I think I'm getting close.

So I can get the adjustable weights for about the same price as the 10-68 weights, so I'm leaning towards the adjustable if I can figure them out. According to the linked manual, the 900 calls for 10-68 weights for 9-11k feet and 10-66 weights for 11-13k feet.

I'm wondering if I get the adjustable weights, is there a known specific way to set up the rivets so that it is the equivalent to a 10-68 weight or do I just have to experiment and keep adding and removing the rivets?

Also, if my target is 10-68, should I get the 71 or 74 gram MTX Weights? Please correct me if I'm wrong, but I can hammer the rivets in and drill them out so they are a one time use. ie if I get the weighting wrong and have to remove rivets they cannot be reused. Will it be easy to figure out where to place the rivets or should I just get the 10-68 fixed weight?

As for max rpms, is that something I can test by elevating the track and then make sure it lines up in the field?

guidoxpress · Nov 30, 2015

This is SLP recommendations for their SLP and Ecu reflash. So you will be throwing less weight for sure.
Do simplicity, I think u should get 10-68 weights. If u travel and ride a lot of diff elevations get the 71g and add 2g to the outter hole in each weight and go from there imo.

Do not try and test rpm or anything for that matter on stand. U will only waste gas. The motor must have a load on it (in snow) In order to get that info.

Sent from my iPhone using Tapatalk

7danie49 · Jan 13, 2016

Hey, guido

First, I wanted to say thanks for all the help getting my sled setup for the altitude. I have ridden her three times now and the engagement and max rmps are right on point!

So I know this probably isn't the right place to ask this, but I figured you'd see this and maybe you have some insight to my problem. So before I rode the sled, I replaced the temperature sensor (the one in the engine). So afterwards, I refilled the coolant and bled the system by elevating the front about 2 feet. The sled was started and moved a couple times in the process of getting it from AK to CO, but not ridden by any means. Before I took it out the first time, I noticed the coolant was low. So I topped it off and rode it the first time. The second time it was low again, so I topped it off again and rode it. The third time it was also low. So i topped it off and rode it again, but this time I had problems.

So while riding, the temp guage ranges from around 105 to 165. In the flats with a couple feet of powder, she ran around 105, while on the groomers she gets really hot. I take her off the trail when I get the chance to cool her down and try to stay under 165. Yesterday when I was riding, she apparently got really hot while climbing a tracked hill, but I didn't notice. I shut it off and a couple of minutes later, antifreeze started overflowing the reservoir and spewing out the top (under the cap). I started her up (temp read 200) and took her off trail to cool her down, but she kept wanting to get really hot again (lost antifreeze, so made some sense to me). I rode her back to the trailer, about 7 miles back, getting off trail a lot to keep her cool. I kept riding her by the parking lot (powder hill) while my buddy got the ramp on the trailer. By the time I got it onto the trailer the temp read 180 and I shut it off for good. Antifreeze again started to overflow for a while.

So I guess I don't really know what is wrong. I've been reading a bit about thermostats and whatnot, but I guess I don't know where to start. Is antifreeze supposed to be able to spew out the top of the reservoir? Any advice on what I should do?

guidoxpress · Jan 13, 2016

Glad the clutching helped.

U must not use ice scratchers? I highly recommend them.

Is ur coolant the 50/50 mix? Should be of coarse.

If u have not replaced the thermostat I would do that first before u sweat it more. They should ideally be replaced every 2-3 seasons at most depending on mileage and report back

Sent from my iPhone using Tapatalk

7danie49 · Jan 14, 2016

Coolant is 50/50 in the bottle, meaning I don't do any mixing. That's what it should be, right?

Is this the right thermostat? I don't need a new cover, right? Should I replace the o-ring too?
https://www.startinglineproducts.co...scription&catalogID=9&catID=68&productID=2682

guidoxpress · Jan 15, 2016

All above is correct!!^^

Cover? What u talking about. U mean the housing? If so..no

The oring isn't usually bad unless it's been pinched. Just swap into new one if good shape

Sent from my iPhone using Tapatalk

7danie49 · Feb 19, 2016

Hello again,

So I think I uploaded a photo of the old thermostat (on the left) and it definitely doesn't look so happy. Looks like it got all bent out of shape somehow. So I swapped the new one in there and bled the coolant. Heres what happened...

Started up and idled for around 20 minutes. Temp gauge went to around 130, then held for a few minutes, then continued to slowly rise up to 170 before I shut it off. I let everything cool off and checked the reservoir for the coolant (the tank you add coolant to) and found that it was completely empty of coolant.

After replacing the coolant, I started it up again and let it idle for 20 minutes. The temp did the same thing and I shut it off at 170. This time, after cooling, the coolant was full to the fill cold line on the reservoir.

Third time, started up for about 30 minutes. Temp held again around 130 for several minutes, but then continued to increase. Around 160 I packed snow on the runners and tunnel, which made the temp decrease to around 140-145, but then it continued to rise until 175 where coolant started to trickle out of the overflow tube on top of the reservoir (the port at the top of the tank, below the cap). Then I shut her off.

I haven't had a chance to test her in the field with snow, but this doesn't seem right to me. Does this seem normal or should it be able to keep itself cool at idle?

Btw, outside temp was in the high 30's.

bigrig · Feb 20, 2016

good move replacing thermostat! every-3 years. of course sled will overheat sitting running for 30 min. sounds like you need to ride that tractor!! scratchers down on trail, watch temp, hang on!!

7danie49 · Mar 3, 2016

Woo! Thanks bigrig and guido. I've taken big red out twice now and she is staying cool. The scratchers are key and keep her right around 130 cruising on the trail in warm weather. I'm starting to get the hang of this sledding thing and man am I addicted. Thanks again for all the help guido

until next time...

7danie49 · Apr 20, 2016

Won't Start

Hey guido,

So I've taken the sled out a good bit this winter and it has been running great, until it stumped me yesterday. First off, let me say that the sled always starts in 2-3 pulls, no matter the temperature. Although recently, if I park on an incline while out riding (i think usually downhill) she is a bit hesitant to start (i just have to give her a little bit of throttle and she is fires right up).

So I was riding and everything was going well, then I parked on down hill where the sled was leaning a bit down and to the right, in order to help a buddy get turned away from the tree. I was parked for well under 5 minutes and then I couldn't get my sled started. My buddy came over to give it some throttle, where it took several pulls to start it up. It turned over and reved up (since we were giving it throttle), but then it shutoff and I haven't been able to get it started since. I have replaced the plugs, taken them out and pulled the cord with the throttle held down, held the throttle down while pulling with plugs in, but no results. It smells of gas after pulling and holding down the throttle. I let it sit overnight and tried again but no luck and I started to smell gas again.

Now when I pull without pressing the throttle, it sounds like it does if you were to have the machine with the kill switch down/key turned off (another words doesn't sound like it wants to turn over at all). When I have the throttle pressed and I pull it, it sounds almost as if it bogs a little and is trying to start. This also happens though when the key and kill switch are turned off (throttle still pressed).

So I'm stumped. The plugs were wet with what I presumed was gas when I replaced them, but no fuel came out of the plug holes when I pulled with the throttle pressed and the plugs pulled out. So do you think she is just flooded or is there a bigger issue at hand? The local shop said they could plug in a diagnostic scanner/code reader which I'm open to the idea of, but will that tell us if there is a problem with the wiring?

guidoxpress · May 6, 2016

Sry for the delay. Mentioning my name doesn't tell me u asked a question lol. Send me a message next time for quicker response.

IMO, I wouldnt sweat it until you actually installed new plugs (gapped correctly) and see if it starts. U could easily have fouled them both from several failed attempt starts

Sent from my iPhone using Tapatalk

7danie49 · Dec 2, 2016

Hey guido

So I got some new plugs, gapped them, and still no luck. I got out the multimeter and started messing around. The only ground I could find, is above (and inside/under the hood) where your left foot stands. Like behind the left compartment. To test for power, I've been connecting to the ground there and pulling the pull start.

I get no power to the coil wires (spark plug wires) nor coming into the coils. However, if I unplug the plug to the key, I have a voltage and current coming into that plug when the red kill switch is up and no power when the kill switch is down. (So I believe the key and red kill switch are working.)

I guess I'm wondering what else I should check. I've been looking at some wiring diagrams online, but everything seems tucked away behind the engine and I can't fit my fat hinds in there. I don't think I'm prepared to pull the engine, so hopefully that isn't the only way. Do you have any idea what could be wrong/ what I should do next??

Thanks!

guidoxpress · Dec 9, 2016

Sorry for the delay buddy super busy

So no spark on plugs, no power in or out of the coils..

Leads to bad/shorting wiring behind ecu, loose connection, bad stator or possibly the gap from the fly wheel to the sensor is too big. There's 2 sensors, one for spark and one for injector pulse timing.

Hopefully some others will chime in for suggestions. If it was me I would pull the tank and start inspecting every wire.

cameronblakeman · Dec 6, 2022

So I recently bought a 2018 rmk 800 and I have 10-62 clutch weights at roughly 2000 elevation and when I rev it it only goes to 6700 rpm isn’t that backward or what’s up with it?

Clutch Weights and Spring

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Active member

Well-known member

Well-known member

Similar threads