Bully clutch questions

giwprez

Member
I have a 3 disk clutch I'm using on a jackshaft... It is NOT the jackshaft clutch. It has worked flawlessly for a year. I've been using the brass weights and red springs.

Is there a reason to switch to black springs? What differences could I expect just changing out springs? I know I'll have to adjust the heights.... But I'm just curious if any other effects will be felt.
 
The black spring is a softer spring then the red one, so it will take less overall force to compress the pressure plate. The black spring will compress faster, but also release slower.

If the springs are too soft, or too much weight is on the levers, you will get a chatter effect.

Im not sure what your engine setup is, but for all the Yamaha KT100 stuff I've built, I've been using the purple .067 springs with straight levers, or .085 black springs with regular levers, 1 set of bolts
 
Last edited:
I use a gator 3 disk with purple springs like the 4 disk bully with a bolt in every other lever. I honestly haven’t thought or bothered to try anything else. I was just always told the open two cycles are harder on the clutch at engagement and build a lot more heat due to us constantly slipping the clutch trying to keep the motors cleaned out. With my 2.71 primary ratio my clutch comes in around 3,775 at the shaft. The wankel I feel would be much more forgiving due to the broad power which is why I think you’ve been able to get away with a standard 4 cycle three disk.
 
I've been able to use it without a single issue.... It's been great. Was just curious what changing springs would do... If one is better vs another.
 
Stay with the red springs and heavy weights if that is working for you.
If you do the math for your jackshaft ratio and know peak torque of your engine, you can use any of the forementioned spring and weight combinations to come up with the correct engagement.
We've built/rebuilt a lot of jackshaft clutches over the years and the biggest issue we see is guys changing their primary and/or not having the clutch set correctly for it.
I prefer the black springs over the purples, especially for consistency and longevity.
The engagement rpm at, or near, peak torque is the critical thing.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Stay with the red springs and heavy weights if that is working for you.
If you do the math for your jackshaft ratio and know peak torque of your engine, you can use any of the forementioned spring and weight combinations to come up with the correct engagement.
We've built/rebuilt a lot of jackshaft clutches over the years and the biggest issue we see is guys changing their primary and/or not having the clutch set correctly for it.
I prefer the black springs over the purples, especially for consistency and longevity.
The engagement rpm at, or near, peak torque is the critical thing.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Thanks for the reply. So the springs won't necessarily change anything other than the ability to engage sooner? The reason I am thinking about changing to the black springs is because I have the adjustments backed out so far to the engagement I'd like that after a couple of races, I no longer have the ability to adjust for wear. So I end up having to tear down the clutch and remove spacers. All things the same... does 3500 engagement with black springs react the same as 3500 engagement with red? How is it different?
 
You have to start at different spring heights to get the same engagement speed. And thats where you are now, springs backed out so far its impractical.
 
Thanks for the reply. So the springs won't necessarily change anything other than the ability to engage sooner? The reason I am thinking about changing to the black springs is because I have the adjustments backed out so far to the engagement I'd like that after a couple of races, I no longer have the ability to adjust for wear. So I end up having to tear down the clutch and remove spacers. All things the same... does 3500 engagement with black springs react the same as 3500 engagement with red? How is it different?
I'm not sure I understand that statement.
The spring height should not be affecting the wear (friction discs?) if the engagement is where you need it.
Wear is wear -- doesn't matter if it's black springs or neon yellow springs.
As far as friction disc wear and maintaining air gap...there are different thickness floater discs available as well, so you can re-use your current worn friction discs longer and still maintain proper air gap.

Now, if you are maxed out on spring height, and you might want to lower the engagement rpm further still, THEN you would need to go to softer springs, since you already have the brass weights on the levers.

We have most any part you would need for your Bully clutch in stock. If you can't find it at your local kart shop - give us a call.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Back
Top