Dry Clutches?

I would have bet a lot of money that you would respond with something like that...… No, it does not count when it's wrong. Continue to wallow in your own ignorance.

Oh, and I have been in karting for 68 years (even before karting officially started) and never met anyone like you, thank god.
Hey - teclittledoggie - perhaps you should listen and attempt to comprehend instead of mouthing off???
 
I know 2 cycle jackshaft clutches typically have a steel basket, purple springs and bolts in every other lever. I have a Sudam, but it’s a 300LB package with the driver. I would think a 4 disk bully is overkill and I have a bunch of 2 and 3 disk 4 stroke bully’s laying around. What’s stopping me from replacing the basket for a steel one, putting in purple springs and bolts in every lever? Any secret sauce that I’m missing or issues with that thought process?

We ran an MDC on our alky K30 with 3 red springs and weighted levers used to set clutch engagement with needed gearing to cause initial clutch engagement at 4cycle briggs rookie engagement of I think i'm remembering correctly 3500rpm. We used mini gears on the axle allowing us to use minimum clutch gear diameters verses regular axle gearing which would need larger diameter clutch gears. The mini gears also allowed for using either left or right engine output via belt to our jackshaft because the chain to the axle mini gears would clear motor mount rails. My theory for using small verses tall clutch gearing was I felt a smaller clutch drive gear would be stressed less moving hypothetical stress in my mind to the axle especially in turns and coming off turns.

In all the years using the setup we only had two problems. One the MDC inner race which slid over the output shaft of the jackshaft would always be cracked. Though always cracked it never failed so it was a non problem. The only other problem we ever had with the clutch setup was we once got a small stone lodged under a clutch lever causing clutch lockup. Found and removed the stone and all was ok. Other then maintain the only other thing I did to the clutch was turn clutch springs in a quarter of a turn when we went to a small track and back out for larger tracks.

Donald Rati originally presented me the idea to do it and he got it from someone years earlier. Donald and I debated till the cows came home tall clutch gear over shorter clutch gear. Over all Donald broke more then we did probably even coming close to how often Mark broke. ... :) So it's tough to say who was right about clutch gear. Over all I feel our setup was far superior in both reliability function then the normal axle clutch setup then used by most back then. One racer who used my setup simply took a stock 6 black spring MDC and used it on his Sudam. I think though he did have some clutch failure where we never did and I attribute it thinking back to our using stiffer fewer springs and more weight.

ps... before we got our MDC we used an old NORAM shoe clutch successfully on our gas and oil yami. LOL, i'm not sure if we effectively had any springs in the NORAM or not??? ... :)
 
As Pete Muller's tech articles said, you should run the heaviest springs and heaviest weights you can for more positive lockup, IIRC. Maybe He'll chime in.


Ted,

I think it depends on the situation: I spent a good amount of time enduro racing, and there were a few times (on lower geared tracks, with certain layouts), when I would find myself tuning the clutch "the other way" -- actually taking out a touch of spring and weight. It was rare, but it happened on particular tracks. Of course on disc clutches, it's also possible to slightly change the action of the clutch by increasing or decreasing air-gap (because it uses a different part of the "cam" to apply the force). Shape of the cam determines a lot, (in relation to air gap).

But... with what most of the people here are doing (at least from what I'm reading): it's often a jackshaft setup, and once the race is on and rolling, the clutch may not slip until the race is over and they're driving back to the pits. If that's the job of the the clutch, then yes... I'd probably be going with a good amount of spring and weight so that the clutch is more positively locked up during the race.

Fwiw: clutches seem to "creep" slightly regardless of what you do to them. Even at peak revs they will be slipping just slightly. Stacking on spring and weight just helps reduce that.

PM
 
I don’t know how this compares to a Sudam...
But I ran my yz144 for years with a 3 disc bully...
I had it engage at 4000rpm on the secondary side of jackshaft...
Engine rpm was 8760...
Regular maintenance, and replace disc’s at the end of the season...
 
I dont understand why people mess with the dry clutches on an open engine. Around here we have to many cautions and it just heats them up and after the second or third restart they are junk compared to a Birky. I hate when people say there is nothing better but I havent found a better clutch for open racing.
 
I dont understand why people mess with the dry clutches on an open engine. Around here we have to many cautions and it just heats them up and after the second or third restart they are junk compared to a Birky. I hate when people say there is nothing better but I havent found a better clutch for open racing.
What’s the trick to getting the Allen screws out of the birky to check it?
 
What’s the trick to getting the Allen screws out of the birky to check it?

Really no good trick. I take the cover off and turn the screws all the way in, check air gap then work myself out to the desired gap and memorize the turns to get to it, put the cover on and repeat.
 
Really no good trick. I take the cover off and turn the screws all the way in, check air gap then work myself out to the desired gap and memorize the turns to get to it, put the cover on and repeat.
I am having trouble get the allens out of the pulley side I presume thats how you get it apart? I didnt know if I was going to break them off or if they are reverse thread or just tight
 

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I like birky clutches a lot of people don’t.they don’t know how to maintain em.if they leak and don’t change belts and use the wrong fluid they run from em.also bc axle don’t free spin on stand..they don’t understand fluid when it’s hot and cold,and when they try to stop the tires w hand on stand.if it didn’t free roll on ground you could push start your kart not the case.my clutch has 5 discs it’s no slouch when it gets warm.all clutches ya have to work on.just a fact.
 
I know the Clutch plates are at least 4 yrs old in the clutch I run.it has new seals and bearings.everything else looks new inside.broke few belts and lost some tranny fluid along the way.
 
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