2010 M8 losing RPM's

[Sleddinvern]

I have a 2010 M8 with a 153" track. I ride at around 9k ft often and cant seem to hold RPM's worth a crap. Initially I had the stock 68g. weights in the primary with the yellow white spring, and the secondary is stock helix and stock orange spring. When in really deep powder it would start out up to 8100 rpm and then by the time i got to the top of the hill it would be down to about 7000 rpms.
So i bought some Cutler adjustable weights and little by little dropped it all the way down to 63g where i am at now. I still have the stock yellow white spring in it. About 200 miles ago i cracked my spider and got a whole new clutch under warranty, but i left my weights at 63g. I just got back from a ride in 24" of moderately light snow and i am STILL not holding RPMs. If my sled is pretty cold it will hold about 8000 rpms, but once i ride in the deep for about 10 minutes it loses most of it's "flickability" and holding a hill is borderline miserable since my rpm's will sometimes creep all the way down to 7100 rpm's.
So i dont know what this could be? i have done nothing to my secondary besides blow it out with compressed air. I dont want to go and spend a ton of money on a secondary clutch kit if that is not the real problem. Hoping for someone with a similar problem or any information would be greatly appreciated. Thank you

 

[WyoBoy1000]

Do you have side vents, are you running a 046 belt, is your clutch offset set at 1.5, are the clutches parallel to each other. do your rollers turn easy, put in a new primary spring, they start to loose tension around 500miles, you might try a SW green/White spring. Are you running a 36* helix. change DD fluid and look for metal in it. Make sure motor mounts are good. Is your track to tight. Any other mods on the sled, do you run a shift assist.

 

[Sleddinvern]

Yes i have side vents and i am running a 046 belt. This is my first cat (far from my first sled) and have never checkd the offset, or if the clutches are parallel, I would hope so since i just got a whole new clutch and would think the dealer would have had to check that to shim it properly. I have traied a spl blue/pink primary spring and that didnt help a whole lot except it made it very high engagement. I am running the stock helix that i believe is a 36*. I change my dd oil about every 600 miles and just changed it before this last ride and no metal flakes were found. I will check the motor mounts and my track is way loose, not even close to too tight. I have zero mods to the sled itself and i do not have a shift assist. I am planning on tearing into the secondary clutch this week to see if the helix is cracked or if the spring is broken somehow???? the rollers seem to roll well, but i dont know if they are getting too hot and not rolling?????

 

[RickM]

sleddinvern

I don't see how many miles are on the sled!. My thoughts are, Have you cleaned the power valves, and the inner part of the cylinders where the power valves move up and down, use brake clean and soft rag to clean cylinder castings where valve slides up and down. Dirty power valves kill the performance.
also check the slack in the power valve cables, there are gauges sold or you can make one your self to check them with. The rollers in the secondary if they are white in color wear after a time. I would check them and if they are worn, install rock rollers. I would check these items first before making a lot of changes and not having a good base line to check from. Hope this helps you out. RickM

 

[diggerdown]

It sounds like you are not backshifting, I would check the secondary over real good.

 

[WyoBoy1000]

Would be a good idea to check powervalves for proper adjustment and that they move free, but I don't think that is it. Can you tell if you are building a lot of heat in the clutches after a pull. I would call the dealer and ask if they did align it and if the checked the motor mounts. Never assume anyone does anything for you, just make sure it will save you money. If they are not aligned right it could over heat the belt causing it to get sticky and pull down rpm. tear down the secondary and make sure all is good. FYI to get the bolts out of the helix you have to heat them to get the loctite loose then they come right out. Have you tried a new belt, old belts can look perfect but screw you bad. Make sure it is a 36* helix and put a new primary spring in if you havent. If you could hit rpm with 68g weights I would add the weight back in and figure out why its not working. I had this problem on my m1000 and it was from not having enough motor mounts and it was pulling the clutches out of alignment and gained nothing from dropping weight, now it works.

 

[samiams2]

Dirty power valves kill the performance.
also check the slack in the power valve cables, there are gauges sold or you can make one your self to check them with.

Who sells gauges to check power valve adjusted?

 

[CO 2.0]

Who sells gauges to check power valve adjusted?

Are you just talking about a caliper? They sell those everywhere. Napa, auto stores, harbor freight etc. I like the digital calipers the best. Quick and easy.

 

[RickM]

gage for power valves

I called my dealer and got the slack measurement for the end of cable.
It will be in thousands of an inch. ( looks like its just over 1 inch or so)
what I did was get a 1/2" wooden dowel, rough cut it to length, used a hack saw blade to cut a groove down the length of the dowel so the cable would lay in it. Then ground the end of the dowel down on bench grinder until I got the Exact length of cable clearance that Arctic Cat recommends using a sliding dial indicator. It cost me nothing to make but my time. You have to unhook the cables at the servo motor to check end play in cable, its easy to do. I just keep the dowel in my tool box for future use. RickM

 

[diggerdown]

35mm or 1.377" of exposed cable for the 800.

 

[montanasledder]

My 09 doing the same thing last weekend, 2-3 feet of new powder. 9000 feet. didnt think i was gonna make it sled rpm's started around 7800 and by the time i got the the top it was under 7000. need to figure it out

 

[m8lovin]

Montanasledder check your Rollers on the primary. Mine did that a few rides ago and I found a bad roller in my spider. Just caught it in time before it took out my weight.

 

[Sleddinvern]

Thank you all for the advice. sounds like i have a lot of work ahead of me. My sled has over 1400 miles on it. It has been doing this pretty much since i bought the sled though(October 2010 new). i will go through some of these checks and see if i find anything suspicious.

 

[WyoBoy1000]

You don't want to run your track to loose, if it is to loose it just gets thrown around and looses momentum, so set it to spec.

 

[jim]

Three things will primarily do that: Primary spring, primary rollers or secondary rollers. I had the same type of issue on my M1000...Rs would drop when it got hot. I put a blue/red SLP spring in primary (stiffer finish rate) and replaced the stock rollers with rock rollers in the secondary. you might go for a bit stiffer finish rate. I think a main culprit is the cruddy stock plastic rollers in that secondary. Some guys have also had luck with using the needle bearing in the secondary...cuts down on binding. Ultimate fix for RPMs all day? RKT secondary kit. Pulls Rs all day. http://www.youtube.com/watch?v=AkFZoeHTvpE

 

[WyoBoy1000]

SLP springs are junk, unless they really changed some stuff lately, I prefer SW springs, there may be some others but slp's suck and have caused more problems then help

 

[jim]

You are killing my buzz wyoboy. Have 1500 miles on the blue/red...still works great.

 

[DPalmerM10]

Polaris black-gray, 100-340 works great, I don't care what Wo-Boy says. He must get a com from SW.

 

[WyoBoy1000]

Polaris black-gray, 100-340 works great, I don't care what Wo-Boy says. He must get a com from SW.

That must be why I crushed a polaris black spring (100/340) in 3 rides to the point it wont shift right and I had to add a .90 shim to make it like it was new. By the way the Black is a 100/340, and I run a Black/Green 120//340 in my turbo and its already loosing its stiffness after a few rides. I have a SW spring with over 500miles and its lost very little of its spring.

So is this black grey spring a new spring or did you get told wrong. Or maybe you should just give info instead of making ASSumptions. O well, seem myself and many others do it once in a while too.

 

[DPalmerM10]

Its a black with a gray spot on it, part# 7043121. As you stated above, "we all make mistakes".