Question on clutching with SLP Pipe Kit on 09 M8 SP 153

[Frostbite]

I'm curious why SLP loads the outer holes on the MTX weights for mountain use?

I played with heavy hitters for years and your inner hole was your mid range adjustment and the tip was your top end or shift speed adjustment. I would think you'd want to load the inner hole before ever putting anything in the outermost holes.

The inner (middle) hole on the heavy hitters was the one you could feel in your arms when you loaded it. The sled pulled like crazy.

Yet, SLP suggest for 6-8,000 feet to use 2 grams in the tip and nothing in the inner hole. It must have something to do with the profile of the clutch weights?

 

[skidooboy]

profiles are everything. you can have a very aggressive profile with lighter weight total mass. or vise versa. the more aggressive the shift curve on the weight (arm) the lighter the weight will need to be. it is all a give and take. there are soooooo many variables the will work and wont work, it boggles the mind.

as stated before there are two schools of thought. light weights and weaker springs or heavy weights and heavy springs. they both make rpms to match the peak torque and hp of the sleds but, they react different. some will pull hard and some wont. that is what testing and tuning gives you.... the information to choose what works for you and your application.

ski

 

[Frostbite]

Yup, once again you nailed it Ski.

I just hate to give up any potential mid range pull by not loading the middle hole. Perhaps loading the tip ensures enough belt squeeze up high? Oh well, I will do as they say.

 

[RickM]

Results from todays test

Well I said I would post the results, there has been lots of helpful comments here while I have been testing. I really appreciate everyones comment.
If you forgot, short recap- 09 M8 153, with slp pipe kit, testing at basicly
11 K elevation.
test #1 cat 68 gr. cat yellow/white, pulls at 7800 RPM
test #2 cat 68 gr. speedwerx red/white, pulls hard at 8000 RPM
test #3 cat 70 gr. speedwerx red/white, pulls like a bull at 7800 RPM.
made several side by side runs with new stock 2010 M8 SP, ran side by side.

I guess I may take some of your advise now and play with the MTX and see how it compares. If the MTX will pull as hard as the cat 70's and reach peak rpm of 8100 that would be the ticket. thanks for your comments and help. RickM

 

[Frostbite]

I think I'm finally close on mine.

I too have an 09 M8 with the SLP single pipe but also the SLP Performance Edition Kit. I have the 74 gram MTX weights (which actually weigh 73 grams empty by the way). I have a 2 gram in the middle hole and 1 gram in the tip. I was using the SLP Black/Pink 120/340 primary spring and loved it. The sled engaged at 3,500ish with no bog whatsoever.

I had BDX cut me a 45/37 multiangle helix. SLP recommended a 44/36 but, I ride under 8,000 feet and I'm well under 200 lbs so I knew I could at least one more angle of helix to try to help achieve a little higher track speed.

I was pulling 8,130 at 6,500 feet. The sled flat out flys now. I want to be at 8,200 so, I drilled out the tip weight for my trip tommorow.

Here's a tip everyone should try. I got a PM regarding my question about stiffer secondary springs after I asked about them in a thread. So, I took the advice and ordered a Fett Brothers silver secondary spring that is rated at 198/288. It wakes up the sled SO MUCH it's incredible. The backshift improved a bunch and the throttle response is right there.

I also just got a Straightline performance 180/315. I plan to try it after tomorrows ride. These stiffer springs help gain a few more RPM on top as well.

 

[sledbilly]

mtx

I have the slp kit on my 09 and struggled with trying to get the rpm's using stock weights with different springs etc. Did not want to shim the spider for the mtx weights and wanted to keep engagement below 4k. I've gotten pretty good at changing weights, bout 10 mins using a cordless to take the cover off.

So as someone else posted I went ahead and tried the MTX weights with an old belt. Made all the difference. Nice engagement and motor spools up to 8000 quick. slp suggests 1 gram in outer hole for 0 to 3000 and revs were just over 8000. I ride mostly at 2500 so I removed the 1 gram and revs now about 8150. I'm also using slp 40/36 helix.

sled just rips. what a difference over stock. I have one last issue that i will post separately but maybe you guys can help. I still have a slight burble off the line that carries further into the rpms the faster i mash the flipper. clears up right away. I'm not sure what a lean vs rich bog feels like. any ideas?

 

[RickM]

Sledbilly

I have my clutch in getting slp to shim spider now.
my question for you on your bog on low end, Do you have the stock intake or have you changed that? Mine is stock intake and no bog/flat spot at all.
RickM

 

[sledbilly]

slp intake

Thanx for asking rick. I do have the slp intake.

Last week I put the stock pipe,y,can back on the sled to see if the bog was still there. Sled ran fine and that was with the slp intake. I also had a bad resonance with the slp setup...really annoying. I tried silicone on the exhaust springs, double springing and neither resolved the resonance. What I found is the flange on the slp can was rubbing on the metal outlet hole....I had siliconed that but it wore through. You could see where the outlet had rubbed a groove into the can flange. A rubber mallet and more silicone and the resonance is gone.

I put the slp kit back on the sled to try and figure out this bog.

Hard to describe the bog/flat spot and I don't know what a lean or rich bog feels like. Easing into the throttle the bog is there til about 4200 or so and then goes away. If you get into the throttle the bog will carry further into the r's and goes away up around 5000. It sort of feels like a shudder in the engine. Feathering the throttle can help make it go away. No issues with the mid/high range.

not oil loading because I tightened up the return spring. There are times that the sled will backfire when starting up. I always let the sled idle down before shutting off so maybe that means it is rich at idle? Plugs look excellent.

 

[RickM]

sledbilly

well i'll take a "stab" at this bog issue, you didnt mention temperatures of engine or outside temps! I would be inclined to try the stock intake with the slp pipe kit, just to eliminate that by its self. Putting the stock exhaust back on created more restrictions which could change the intake input needed.
Also simple little things like new spark plugs, easy to over look. I put in new set of 4 each fall. I presume you have your oil ratio figured out, I set mine at 40-1, A rich oil mixture could also effect your low RPM burn. Im just trying to think what all could give you frustration. Try the intake swap, let me know.

 

[RickM]

Ttt

 

[chuckbernard]

Which MTX weights did you use? 71g? That is what they recommended to me for my '09 M8 HCR with their single pipe kit and intake. They also recommended their 40/36 helix. I will install the weights and helix and post the results.

My 70g Arctic Cat weights give me 8100 rpm on flat roads with packed snow but once I hit a hill with deep powder I'm getting 7800rpm and a track speed right around 40mph.

I have the slp kit on my 09 and struggled with trying to get the rpm's using stock weights with different springs etc. Did not want to shim the spider for the mtx weights and wanted to keep engagement below 4k. I've gotten pretty good at changing weights, bout 10 mins using a cordless to take the cover off.

So as someone else posted I went ahead and tried the MTX weights with an old belt. Made all the difference. Nice engagement and motor spools up to 8000 quick. slp suggests 1 gram in outer hole for 0 to 3000 and revs were just over 8000. I ride mostly at 2500 so I removed the 1 gram and revs now about 8150. I'm also using slp 40/36 helix.

sled just rips. what a difference over stock. I have one last issue that i will post separately but maybe you guys can help. I still have a slight burble off the line that carries further into the rpms the faster i mash the flipper. clears up right away. I'm not sure what a lean vs rich bog feels like. any ideas?

 

[sledbilly]

chuckbernard

I believe the weights SLP sent me were the 77g with 1g to be added in the outer hole for 0 to 3000'. I removed the 1g to get my rpm's closer to 8100.

do you have any issues with a low end stutter on the motor?

 

[RickM]

Great Service From Myron at SLP on Tuesday

Well Here it is, Sled Flat Rips. I started this thread way back last fall.
Trying to figure out clutching using cat weights. Finally broke down and had my spider shimed. Heres the Deal.
I called SLP monday morning and asked how much it cost to shim spider and how soon could they do it. I shipped my clutch to SLP on monday FedEx.
They got it Tuesday morning, Myron shimed the spider, balanced the clutch and called me Tuesday afternoon to let me know they were shipping it back.
Got my clutch today on Fed Ex 2nd day air. Installed and went test riding.
Sled now kicks **tt. Now that is top notch service if you ask me. Thanks SLP.
Here is my set up as of today.
09 M8 Sp 153, SLP pipe kit, shift assist, 40/36P Helix. rock rollers.
MTX 71 gr weights, 1 gr rivet in tip. Speedwerx Red/White 125/340 pri. spring.
(set for 10k-11K) engagement is smooth, can walk it easy. engages at 3600
RPM. Pulls 8100/8150, holds RPM doesnt drop. Has strong bottom,mid range.
this is what I have been looking for. Excellent for short test today, Rickm

 

[RickM]

continued post from RickM

Just one other thing or two,

The motor sounds so much better running up at 8100 compaired to down at 78 or 7900 RPM, its just on the pipe where it should be.

While riding today I checked shive temperatures on both drive and driven clutchs, was only warm to touch, but even between both, ( I have vents)
I marked pri. shives with marker, and it shows belt going up to the top at full shift on flat run.

I checked plugs and they were a nice light tan, a lot cleaner burn than down at 7800 RPM.

This was a afternoon test, Not 3 foot of powder, but was able to load the motor and see results that really impressed me. Im glad i finally shimed the spider after all this time. Hope this helps out with the info. RICKM

 

[Headrush]

I was able to pull around 8,200 R's with my 07 M8 153, at about 6,500 ft. with 68g Cat weights, RKT straight 34 cut helix. When I got up higher I was only pulling about 7,850 -7,900 R's.

I am thinking of getting some Cutler adjustable's and drop down to 66g weights - anyone going this light?

Also, I am a big guy weighing about 280 lbs. not sure how much that is playing into this.

Any ideas?

 

[RickM]

Headrush

Droping from a 68 to 65, I lost a lot of pulling power, didnt load the motor hard with the 65's, pulled RPM but lost pull. You may want to try a higher finish rate on your primary spring. It may raise your peak RPM back up some for you. Hope this helps you out. RICKM

 

[Headrush]

^^

That's what I am worried about too. I currently have the Cat orange/white spring in there now, is there something else I should be running that will get me an extra 2-300 RPM's?

 

[Box Stock]

First off I would like to thank Rick for all of the good and honest info. It really helps us flatlanders out a lot when we don't get all the opportunities to test setups at higher elevations, just lucky enough to get out to the mountains a few times in a year. I was jus wondering if u or anyone else had tried speedwerx lighter tipped weights, like a 69.5g or a 71.5g weight. I have the same setup as u (122/340 primary spring, 40/36 helix) just to the point of deciding on the mtx weights or not. Had some speedwerx weights though that I wanted to try first. Love that primary spring by the way, real nice engagement and holds rpms well.

 

[RickM]

Headrush----Boxstock

Headrush, if I were you I would try the speedwerx red/white 122/340 H5 primary spring. It may help raise your top RPM. When I was testing yesterday I tested a cat yellow/white and then changed to the red/white. I raised MY application several hundred RPM. Im very happy with it now.

As for BoxStock,I have not tried speedwerx light tip weights. so I cant say. but I put off shiming my spider because i heard bad stories about pulling threads on spider when they take it apart. I worked with cat 68,s and the red/white, pulled hard at 11K elevation. just never got top RPM like i wanted.
Broke down,called SLP and they shimed the spider, MTX now loads motor hard, and runs at 8100, what a difference. I want to hit the deep powder this weekend if possible and give it a full test.RickM

 

[Headrush]

Thanks Rick - I will score one of those. What do you think about the Cutler adjustables? Worth a shot for a fine tune?