Bully set up

B

bullerman

Member
Bully 2 disc 6 spring ( red ) starting off set up. Unrestricted Clone in 265 lb
Class. I have looked at Bullys set up sheet. Just wondering if everyone is close to it. Will be running a very short tight turn track. Will need a good launch. Thanks
 
We used bolts in the outer holes and set it around .240 with red springs. Air gap a little bigger out to like .030. I believe we were like 3500-3600 lockup. No longer run it tho my brother liked the feel of the Vortex better so he stayed with those.
 
Either of OvalTech and JPM's set ups will work just fine. Should be closer to 3800 though in my opinion.
Set it to match peak torque of your engine. I prefer the single bolt and nut in the outer hole of each lever, springs at .240," but JP's set-up works also - just has a different engage/disengage feel that you may, or may not, want on your bullring track.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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31 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Should I say will it launch the same both ways I guess is what I am asking. It seems like it might engage quicker with one bolt in the lever.
 
No, it'll engage at whatever rpm it is set at. There are a variety of ways to set up a clutch to engage at the same rpm.
It depends on the application too. It's generally better to use heavier weights and stronger springs as the horsepower increases.
But, the heavier weights take longer to disengage. This can be an advantage, or disadvantage, depending on your track configuration.
Air gap is the single biggest thing that makes the clutch "hit," or feel, different at engagement rpm. The weights, levers, spring pressures, surface finish, all affect it as well, but that's going to be the biggest factor in that "feel" that guys want.
Some designs react very differently as well. The SMC clutches, for instance, don't have that "hit" and have a gradual engagement that some racers like while others do not. It's not better or worse, (depending on who you ask,) it's simply different.
 
Brian,
weights in outer hole hit harder with larger .040 or smaller .030 air gap
I assume will be harder yet if you add 2nd set of weights and raise spring tension
 
whfy39 said:
Brian,
weights in outer hole hit harder with larger .040 or smaller .030 air gap
I assume will be harder yet if you add 2nd set of weights and raise spring tension
Click to expand...

Bigger air gap will give you that harder "hit" or engagement.
More weights and higher spring pressures may help some with engagement feel, but that's not the real benefit - there are other benefits that far outweigh the "feel." Some being the quickness, consistency, reduced chatter, and how (and when) the clutch disengages.
 
Bigger air gap will give you that harder "hit" or engagement.
More weights and higher spring pressures may help some with engagement feel, but that's not the real benefit - there are other benefits that far outweigh the "feel." Some being the quickness, consistency, reduced chatter, and how (and when) the clutch disengages.

Thanks agian
 
It's really amazes me how many different ways there are to set up a clutch. Apparently they all work to the owners satisfaction.
I've always found that if you set the clutch to slip at the engines peak torque RPM you get the most acceleration off the corner. If you're getting peak torque to the rear axle, you have peak HP at the axle. In my "experience", there's no better way to set-up a clutch, period.
 
alvin l nunley said:
It's really amazes me how many different ways there are to set up a clutch. Apparently they all work to the owners satisfaction.
I've always found that if you set the clutch to slip at the engines peak torque RPM you get the most acceleration off the corner. If you're getting peak torque to the rear axle, you have peak HP at the axle. In my "experience", there's no better way to set-up a clutch, period.
Click to expand...
Further proof you do not understand anything you have been told about stock class 4 cycle oval racing.
I suspect most of what I am about to say applies to 2 cycle oval racing


If your clutch is slipping at any time while the green flag is out, you are giving away the farm.

Clutch slip simply converts torque to heat instead of acceleration.

If you are anywhere near peak torque after the green waves, you are in the way.
 
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Al,

I can say without question that in all the races I managed to win, I've never slipped the clutch at peak torque -- always well below. My focus was (and still is, when helping the people I assist in vintage racing) keeping the clutch engaged as much as possible, and working with a balance between engagement characteristics of the clutch, gear ratio, and exhaust pipe. Even in the 100cc Open engines I ran in road racing, peak torque of that engine was above 11,000, yet the fastest way around the track was typically slipping between 9400 and 9700, depending on the track.

Also... all clutches "creep" to some degree... even at near peak RPM. Messing with *how* the clutch engages, and also tweaking the setup so the clutch will pull hard a good bit below peak torque helps to lessen that creep at higher rpm.

Slipping at peak torque is (in my experience) a good way to cook lining (if it's a lined friction surface) and just generally overwork/overheat the clutch.

PM
 
Pete_Muller said:
Al,

I can say without question that in all the races I managed to win, I've never slipped the clutch at peak torque -- always well below. My focus was (and still is, when helping the people I assist in vintage racing) keeping the clutch engaged as much as possible, and working with a balance between engagement characteristics of the clutch, gear ratio, and exhaust pipe. Even in the 100cc Open engines I ran in road racing, peak torque of that engine was above 11,000, yet the fastest way around the track was typically slipping between 9400 and 9700, depending on the track.

Also... all clutches "creep" to some degree... even at near peak RPM. Messing with *how* the clutch engages, and also tweaking the setup so the clutch will pull hard a good bit below peak torque helps to lessen that creep at higher rpm.

Slipping at peak torque is (in my experience) a good way to cook lining (if it's a lined friction surface) and just generally overwork/overheat the clutch.

PM
Click to expand...
It's been my experience, that the KT100 reaches peak torque right at 10,300, and peak HP right at 11,300. The exhaust port opening is at 92° ATDC.
I would be interested in hearing where your exhaust port opening was. Where did your engine's reached peak torque and peak HP. I don't have any numbers on area/Time, but if you do, I would be interested in knowing how your engines compared to a stock engine. The only rotary valve experience I have is with a stock K78. I only ran that engine with direct drive and never had it on a dyno. I did pretty good, winning Norcal Stock Foreign Sprint. That was in 1977, maybe 76. 43 years ago, can you believe that?
 
Leaving this on topic here for bullerman -- "clutch setup"

If you want to discuss RV engines, best to start a new thread in the 2-cycle forum.

PM
 
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