So if my Primary gets hotter than my secondary???

AKpow · Mar 12, 2010

What should i be looking at to change. I'm running a 11" STM secondary That is aTorsional setup not like the stock Compression setup, and dropped a buttload of weight from 77g to 68g and definatley need to take more out if i get above 3000'. Below 3,000' RPMs are at 7,500 to 7,700 mayeb 7,800 (in powder and hillclimbs) I blew a belt for the first time the other day. I'm not sure if the belt was just so abused from me tuning the clutches all winter (ie. Getting alignment and Clutch weights correct) or if i had just been over abusing it that day. It was an Ultimaxx belt and it went KABOOM.

This is on an 07 M8

WyoBoy1000 · Mar 12, 2010

if the primary is hotter its slipping more, you could drop weight but it will decrease the side pressure and could make the primary slip more. Or you could adjust your secondary, stiffening the spring should keep it from up shifting to far and bring up your rpm, which should let the primary catch up and maintain grip.

AKpow · Mar 12, 2010

Thanks dude, i will give it a shot. Correct me if I am wrong, but it would be to my advantage to tighten the secondary spring on deep days, and have a looser setting on sub-par snow days or spring snow?

DonoBBD · Mar 13, 2010

AKpow said:
What should i be looking at to change. I'm running a 11" STM secondary That is aTorsional setup not like the stock Compression setup, and dropped a buttload of weight from 77g to 68g and definatley need to take more out if i get above 3000'. Below 3,000' RPMs are at 7,500 to 7,700 mayeb 7,800 (in powder and hillclimbs) I blew a belt for the first time the other day. I'm not sure if the belt was just so abused from me tuning the clutches all winter (ie. Getting alignment and Clutch weights correct) or if i had just been over abusing it that day. It was an Ultimaxx belt and it went KABOOM.

This is on an 07 M8

What is your belt to sheave and roller to weight? If using stock profile weights you need to run a .060-.070 total. IF you have .020 belt to sheave and .050 roller to weight your good.

When I have encountered this where the primary is hotter than the secondary the mass center line of the weight needed to move more to the tip.....or the weight gets more swing before the sheave touches the belt.

The cheap skuzy way to fix it to measure what you have and what you need then grind a flat spot on the weight right where the roller mark is starting to put a mark on the weights. A 1/2" wide grind will pull .0063% out of the total weight of the weight but it will shift like the same weight.

With all the belt surface area in the 11" your over powering the primary for sure and you may need more weight swing before the belt is grabbed. I would start with a total of .070". IF your starting to see grooving low in the primary even if you have a total of .070 you will need more weight swing for your combo. This grooving is from the cords in the belt and the belt slipping down low in the primary.

Another problem with the 11" is you will need to move the motor over if you didn't to get the belt aligned correct. PTO side out .125" to start if not more.

Don.

600ho · Mar 18, 2010

This is the problem I have been battling since I switched to cat a few years ago. So far not much luck in solving the problem.

Less weight=more slip
More weight=less slip
Loosen secondary (via helix or spring)=slower backshift and less rpm (but cooler clutches).

So what is the solution to maintaining rpm and lowering primary temps/slip?

Im thinking lower gears, maybe an 060, and lots of vents? Maybe even a different profile of weights? Just throwing it out there.

WyoBoy1000 · Mar 22, 2010

600ho said:
This is the problem I have been battling since I switched to cat a few years ago. So far not much luck in solving the problem.

Less weight=more slip
More weight=less slip
Loosen secondary (via helix or spring)=slower backshift and less rpm (but cooler clutches).

So what is the solution to maintaining rpm and lowering primary temps/slip?

Im thinking lower gears, maybe an 060, and lots of vents? Maybe even a different profile of weights? Just throwing it out there.

its the combination that will make the diff, it all has to work the same at the same time. try more weight with a stiffer primary spring its the easiest and sometime the best.

AK737 · Mar 23, 2010

Check your track tension. Had a primary a couple years ago that after 5 miles would darn near be red hot. Had nothing to do with the clutch set-up, just the track was too tight. Cheap easy fix!

AKpow · Mar 23, 2010

WyoBoy1000 said:
its the combination that will make the diff, it all has to work the same at the same time. try more weight with a stiffer primary spring its the easiest and sometime the best.

by stiffer, do you mean a higher finish rate? if so that makes sense to me. i will try it

CATSLEDMAN1 · Mar 24, 2010

all good suggestions, also try running less belt deflection, take the slack out of your belt until it just doesn't squeal at idle, same issure as too much side clearance on belt, when the belt is loose.............it allows your primary to close to far / or gear up to high before the sled is moving.........with a loose belt this happens through the entire shift range putting too much stress on the primary gripping the belt making it more likely to slip and also puts the two clutch's into un complementry shifting characteristics often resulting in a very lazy feeling sled..........moves out ok, but not very inspiring likes it almost sick.

600ho · Mar 24, 2010

Thanks for the comments on this.

I would just like to add when I had a torsional kit everytime I would loosen the spring tension the primary would run cooler. Just what I was looking for. Now the problem with that (as most know) is the the backshift and rpm suffered.

-I started with the green spring and it would backshift and hold rpm like nobodys business, but unfortunately primary was very hot.
-Then i took tension off and even switched to the red/white. Rpm consistency would now vary more, but the primary would run cooler but still hot.
-Then for kicks and giggles i ran the yellow spring. Primary ran even cooler but would not hold rpm at all.

I really dont know where i was headed with telling you all that other than giving some real world results and hopefully getting some more comments and information. And yep, i have read the clutch handbook. :face-icon-small-con

Runner8 · Mar 25, 2010

Less weight

600ho said:
Thanks for the comments on this.

I would just like to add when I had a torsional kit everytime I would loosen the spring tension the primary would run cooler. Just what I was looking for. Now the problem with that (as most know) is the the backshift and rpm suffered.

-I started with the green spring and it would backshift and hold rpm like nobodys business, but unfortunately primary was very hot.
-Then i took tension off and even switched to the red/white. Rpm consistency would now vary more, but the primary would run cooler but still hot.
-Then for kicks and giggles i ran the yellow spring. Primary ran even cooler but would not hold rpm at all.

I really dont know where i was headed with telling you all that other than giving some real world results and hopefully getting some more comments and information. And yep, i have read the clutch handbook. :face-icon-small-con

Have you tried dropping weights?
I run a 07 M8, 75g, RKT sec, 0-3000ft. Running the green spring in 2nd hole it was very snappy, but the primary was hot. Could not hold my fingers on sheeves for more than 3-4 sec. Secondary was cooler. Pulled rpm like a champ, but I felt that it would not shift out. I`ve switched to red/white in sec, 5th hole. Haven`t tried it, but I`m assuming the primary temp would drop, but also the top rpm will drop. Then I have 73g weights on the shelf.. Running the SLP pipe setup, I need to be in the 8-8100rpm range...

600ho · Mar 25, 2010

Runner it sounds like you are going through the same process i was. Honestly i didn't lighten up my weights. When i would loosen up my secondary it would still peak up to the rpm i was shooting for but settle down a few hundred shortly after. I guess maybe a should have tried it but i didn't want the primary to slip more, and generally speaking ligher weight = more slip. All this was on a 08 m8 slp rkt 36*. I currently have a 10 m8 and primary is still slipping a noticalbe amount more than the secondary. Still just looking for cures. Let us know your tunning results. Thanks.

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So if my Primary gets hotter than my secondary???

AKpow

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