Arctic Chat : Arctic Cat Forum banner

How to tune a clutch

33K views 11 replies 10 participants last post by  superjuice 
#1 ·
OK, when do you want heavy weights and when do you want light weights.
Is it just elevation that makes the difference, or does powder v. trails make a difference too?

Just a good beginner course of clutching 101 would be great. Whether it's a link or an explanation.
 
#2 ·
I think if someone has any info, this would be great. I have spent hours searching and have found some good info on what effects different things have on clutches, but to have it all in one spot would be great. Only think I know is:

Heavier weights = lower engagement RPM
Heavier Primary spring = higher engagement RPM

Tighter secondary spring = higher shift RPM

Adjustments to the weights and primary spring also effect shift rate and such, and that is all way beyond me... hopefully someone chimes in who really knows what they are talking about
 
#4 ·
O-K, Here are some basics.
Heavier weights will produce more belt "grip" pressure and lower rpm's, because they will cause the primary to close, or "shift out" sooner.
The more added weight will cause more centrifical force and push the primary spring in "harder"

The stiffer primary spring will produce more rpm, unless you have heavier weights to squish it shut, then it just squeezes the belt more, and "loads" the motor.

There are two different # figures given with each spring (eg. 120#-310#)

The first figure (120#) is how much "force" is required to engage the primary.

The second figure (310#) is how much "force is required to fully compress the spring. (wide open, full shift)

The secondary spring is only calibrated with one figure (eg. 80#)

This is how much "force" is required to fully compress the spring at full shift.( I belive when it is placed in the "center" hole)

On a secondary clutch, you will see that there are several holes drilled in the cover that holds the spring.

If you move the spring into a different hole, let's say clockwise, you will be putting more per-tension in the spring, and adding more spring "force" and top end rpm's.

For each hole you move the spring, it is roughly a 100rpm increase or decrease, (if you loosen the spring).

Now we can talk about helix angles.
Some are what's called a straight cut helix (eg. 55*) while others are multi cut (eg. 60*-40*)

The steeper the angle (60* vs. 40*) means that it will open up the secondary clutch "faster" than a 40* helix.

When the clutch opens faster, the motor will get "loaded" more, resulting in a rpm decrease. This is why you will see more twins with a multi angle helix than tripples, because they make more torque at lower rpm's than tripples, although most all sleds now are running multi's. The more torque that a motor has, the "steeper" of an angle you can use.

I hope that this can help you find the right setup for your machine.
Just remember that there is no "perfect" set up that will do everything just right, otherwise I think that I would have found it by now!
Clutch tuning is somthing that takes countless hours of testing on the dyno, trail, or track, so don't be discouraged if you don't find the perfect combination for how you ride the first time...and remember to only change one thing at a time whene your testing. That is the best way to keep track of your progress. -Catracer343
 
#5 ·
Originally posted by 720@Dec 20 2005, 03:38 PM
Hey Sargent Shultz The best thing out there is the Aaen clutch tuning handbook. Its not listed on their web site but they do have the book. Aaen
<div align="right"><{POST_SNAPBACK}>
[/quote]


LOL...whats the Shultz comment for? Are you saying he's a fat german dumbass? slaphappy Man, that was like one of my favorite shows when I was 9-10 yrs old!! Thats coming from WAY back there!! "I know NOTHING". Cat happy
 
#6 ·
Originally posted by catracer343@Dec 20 2005, 04:22 PM
O-K, Here are some basics.
Heavier weights will produce more belt "grip" pressure and lower rpm's, because they will cause the primary to close, or "shift out" sooner.
The more added weight will cause more centrifical force and push the primary spring in "harder"

The stiffer primary spring will produce more rpm, unless you have heavier weights to squish it shut, then it just squeezes the belt more, and "loads" the motor.

There are two different # figures given with each spring (eg. 120#-310#)

The first figure (120#) is how much "force" is required to engage the primary.

The second figure (310#) is how much "force is required to fully compress the spring. (wide open, full shift)

The secondary spring is only calibrated with one figure (eg. 80#)

This is how much "force" is required to fully compress the spring at full shift.( I belive when it is placed in the "center" hole)

On a secondary clutch, you will see that there are several holes drilled in the cover that holds the spring.

If you move the spring into a different hole, let's say clockwise, you will be putting more per-tension in the spring, and adding more spring "force" and top end rpm's.

For each hole you move the spring, it is roughly a 100rpm increase or decrease, (if you loosen the spring).

Now we can talk about helix angles.
Some are what's called a straight cut helix (eg. 55*) while others are multi cut (eg. 60*-40*)

The steeper the angle (60* vs. 40*) means that it will open up the secondary clutch "faster" than a 40* helix.

When the clutch opens faster, the motor will get "loaded" more, resulting in a rpm decrease. This is why you will see more twins with a multi angle helix than tripples, because they make more torque at lower rpm's than tripples, although most all sleds now are running multi's. The more torque that a motor has, the "steeper" of an angle you can use.

I hope that this can help you find the right setup for your machine.
Just remember that there is no "perfect" set up that will do everything just right, otherwise I think that I would have found it by now!
Clutch tuning is somthing that takes countless hours of testing on the dyno, trail, or track, so don't be discouraged if you don't find the perfect combination for how you ride the first time...and remember to only change one thing at a time whene your testing. That is the best way to keep track of your progress. -Catracer343
<div align="right"><{POST_SNAPBACK}>
[/quote]
Great explanation! Some other rules of thumb....

You tune your primary to control RPM's. That's it!! Pick a primary spring finish force first which will give you the proper shift. You can always pick the engagement later, but you need to get the shift pattern right first.

Helix is for controling the belt squeeze in the upshift and backshift. Secondary spring is a fine tuning device for the squeeze, ie: efficiency of the clutch. Usually you want to keep the secondary spring in the centre hole. Ideally you want just enough belt squeeze to keep the belt from slipping, but not so much that you lose efficiency. Belt slip or too much belt grip and you lose HP to the track. But, if you want alot of backshift, then you give up some efficiency to achieve this since you will be using helix finish angles and springs that will grip the belt hard.

If you need more or less RPM's from there, you change weights to adjust.
Each gram in weight is between a 100 to 200 RPM change.

Biggest rule....you want clutches that are cool to the touch after a good run. This means you are achieveing good efficiency.

Clutch kits are good for all around riding. There is nothing like setting up a clutch for your riding style, riding conditions, body weight, track size, engine mods, etc., etc.

Everything you read here is a simplification. Get Olav Aaens Clutch Tuning Handbook. Really great for understanding the theory. Then it's all about testing, testing, testing. It can be really frustrating, but alot of fun when things start getting close.
 
#7 ·
I guess I should have noticed the description line the first time I looked at this topic and I would have known where the Shultzie comment came from huh? I'll try to pay closer attention to such things.

Don't forget it can also be expensive and addicting..... as you buy more and more and even more clutch parts to play with. This is NOT a bad thing. Keeps you out of the bar if you are spending your drinking money on clutch parts. It just seems like every time you get something "good" you come up with an idea or a "what if" question in your head and you go buy more parts to see if it will work out as you thought it might. The learning process is such a blast, I can't remember having this much fun on anything else in a long time.
 
#8 ·
Originally posted by Jeff H@Dec 21 2005, 11:07 AM
I guess I should have noticed the description line the first time I looked at this topic and I would have known where the Shultzie comment came from huh?  I'll try to pay closer attention to such things.

Don't forget it can also be expensive and addicting..... as you buy more and more and even more clutch parts to play with.  This is NOT a bad thing.  Keeps you out of the bar if you are spending your drinking money on clutch parts.  It just seems like every time you get something "good" you come up with an idea or a "what if" question in your head and you go buy more parts to see if it will work out as you thought it might.  The learning process is such a blast, I can't remember having this much fun on anything else in a long time.
<div align="right"><{POST_SNAPBACK}>
[/quote]
Ditto!!
 
#11 ·
Originally posted by ZRrrr+Dec 21 2005, 10:52 AM--><div class='quotetop'>QUOTE (ZRrrr @ Dec 21 2005, 10:52 AM)</div>
<!--QuoteBegin-catracer343
@Dec 20 2005, 04:22 PM
O-K, Here are some basics.
Heavier weights will produce more belt "grip" pressure and lower rpm's, because they will cause the primary to close, or "shift out" sooner.
The more added weight will cause more centrifical force and push the primary spring in "harder"

The stiffer primary spring will produce more rpm, unless you have heavier weights to squish it shut, then it just squeezes the belt more, and "loads" the motor.

There are two different # figures given with each spring (eg. 120#-310#)

The first figure (120#) is how much "force" is required to engage the primary.

The second figure (310#) is how much "force is required to fully compress the spring. (wide open, full shift)

The secondary spring is only calibrated with one figure (eg. 80#)

This is how much "force" is required to fully compress the spring at full shift.( I belive when it is placed in the "center" hole)

On a secondary clutch, you will see that there are several holes drilled in the cover that holds the spring.

If you move the spring into a different hole, let's say clockwise, you will be putting more per-tension in the spring, and adding more spring "force" and top end rpm's.

For each hole you move the spring, it is roughly a 100rpm increase or decrease, (if you loosen the spring).

Now we can talk about helix angles.
Some are what's called a straight cut helix (eg. 55*) while others are multi cut (eg. 60*-40*)

The steeper the angle (60* vs. 40*) means that it will open up the secondary clutch "faster" than a 40* helix.

When the clutch opens faster, the motor will get "loaded" more, resulting in a rpm decrease. This is why you will see more twins with a multi angle helix than tripples, because they make more torque at lower rpm's than tripples, although most all sleds now are running multi's. The more torque that a motor has, the "steeper" of an angle you can use.

I hope that this can help you find the right setup for your machine.
Just remember that there is no "perfect" set up that will do everything just right, otherwise I think that I would have found it by now!
Clutch tuning is somthing that takes countless hours of testing on the dyno, trail, or track, so don't be discouraged if you don't find the perfect combination for how you ride the first time...and remember to only change one thing at a time whene your testing. That is the best way to keep track of your progress. -Catracer343
<div align="right"><{POST_SNAPBACK}>
Great explanation! Some other rules of thumb....

You tune your primary to control RPM's. That's it!! Pick a primary spring finish force first which will give you the proper shift. You can always pick the engagement later, but you need to get the shift pattern right first.

Helix is for controling the belt squeeze in the upshift and backshift. Secondary spring is a fine tuning device for the squeeze, ie: efficiency of the clutch. Usually you want to keep the secondary spring in the centre hole. Ideally you want just enough belt squeeze to keep the belt from slipping, but not so much that you lose efficiency. Belt slip or too much belt grip and you lose HP to the track. But, if you want alot of backshift, then you give up some efficiency to achieve this since you will be using helix finish angles and springs that will grip the belt hard.

If you need more or less RPM's from there, you change weights to adjust.
Each gram in weight is between a 100 to 200 RPM change.

Biggest rule....you want clutches that are cool to the touch after a good run. This means you are achieveing good efficiency.

Clutch kits are good for all around riding. There is nothing like setting up a clutch for your riding style, riding conditions, body weight, track size, engine mods, etc., etc.

Everything you read here is a simplification. Get Olav Aaens Clutch Tuning Handbook. Really great for understanding the theory. Then it's all about testing, testing, testing. It can be really frustrating, but alot of fun when things start getting close.
<div align="right"><{POST_SNAPBACK}></div>
[/b][/quote]
So if I wanted to go faster then I would have to go with a stiffer primary clutch for the RPM and a softer secondary clutch.
 
#12 ·
just a sugestion... when ur messin with clutches... just keep an eye on engine too... ie plugs... u start workin that puppy harder, gonna mean hoter engine temps and possible lean conditions... not tryin to discourage... just a reminder.. seen too many guys here install a clutch kit, go for a ride and BOOM!!... no more engine :( :(
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top