Ted , Bystrom had a dry enduro axle clutch years ago. Some are still using them in the Yamaha class and the vintage lay downs. I wish I knew that you were messing with that stuff because I just gave 3 of them and tons of spares to a fellow racer in the Pittsburgh Pa. area. Not a bad clutch back in the day but not so user friendly at the track. See ya at Daytona later Chuck.
2 disc or 3 disc - 100cc Limited UAS
- Thread starter Ted Hamilton
- Start date
Brian Montgomery
Member
Yes, where else would you use a Birky? Its a J/S clutch.
Pete_Muller
Moderator
Chuck,
Back when i ran a Bystrom (mostly on an Open engine), the trick was to add some weight to the shoes, and run stronger springs. (little steel balls in the tube were only used for fine tuning). Those clutches worked much better with more spring and more weight.
fwiw...
PM
Back when i ran a Bystrom (mostly on an Open engine), the trick was to add some weight to the shoes, and run stronger springs. (little steel balls in the tube were only used for fine tuning). Those clutches worked much better with more spring and more weight.
fwiw...
PM
Brian Montgomery
Member
450-460# depending how many cheeseburgers I ate that day.
125lbs heavier than me. no wonder your burning up clutch's. 325lb on a BRC 150
alvin l nunley
Site Supporter
Shannon, I believe you're sitting on the front porch worrying and watching the grass grow.
The middle disk are writing on a spline, they'll move much out of Concentra city with a hub. The friction disk are held in place by the drum, they can't move much out of Concentra city either. The fact that we don't feel the lot of vibration tends to confirm that. In any case, the design of the friction discs don't allow them to get, even with some non-concentric movement, out of alignment with the floater disks.
Have been perfectly flat floaters in fiction this, I agree, cannot be bad, and probably more efficient, but significantly better?, I have my doubts. I'm pretty sure if one was more efficient than the other, more heat would be generated by the less efficient components. If am sure, with a heat gun, you could verify that. One thing I'm certain of, if there is extra heat, that would be the only indication that less power was going to the axle.
The middle disk are writing on a spline, they'll move much out of Concentra city with a hub. The friction disk are held in place by the drum, they can't move much out of Concentra city either. The fact that we don't feel the lot of vibration tends to confirm that. In any case, the design of the friction discs don't allow them to get, even with some non-concentric movement, out of alignment with the floater disks.
Have been perfectly flat floaters in fiction this, I agree, cannot be bad, and probably more efficient, but significantly better?, I have my doubts. I'm pretty sure if one was more efficient than the other, more heat would be generated by the less efficient components. If am sure, with a heat gun, you could verify that. One thing I'm certain of, if there is extra heat, that would be the only indication that less power was going to the axle.
Brian Montgomery
Member
Heck didn't have time to burn them up, breaking hubs were the worst thing.
Ted Hamilton
Helmet Painter / Racer
UAS rules for piston ports are 130# plus 1#/cc....that puts me at a theoretical base weight of 230#. With me weighing in at 170#, at the moment (hoping to lose 20 by summer), that leaves me 60# for a chassis... I guess I'd better get a SAE frame filled with helium.... 
Realistically, I think I can get to combined weight of #300 without too much trouble. Should be fun. The CUAS Limited Allstars are at 350#, so I'll have to find a modular weight system.
What does a bare chassis (roller) weigh these days? I was figuring around 100#
Realistically, I think I can get to combined weight of #300 without too much trouble. Should be fun. The CUAS Limited Allstars are at 350#, so I'll have to find a modular weight system.What does a bare chassis (roller) weigh these days? I was figuring around 100#
Brian Montgomery
Member
At 130# base weight a set of dual Comer P51's would be stout especially with Sudam pistons.
Ted Hamilton
Helmet Painter / Racer
@Pete_Muller -- here's a peak at what I was working on...I should have added one more item to my post above -- which rainman eluded to: the exhaust pipe.
So let's change my previous post to: a combination of weight and gear ratio, PLUS the power characteristics of the exhaust pipes.
Be on the "wrong" side of all those, and keeping a clutch alive for any length of time is a challenge at best. Be on the good side (light kart, low gear ratio, and an exhaust pipe with a broader/softer powerband), and a light, possibly single-disc clutch will last a long time.
- - - -
Ted,
Something to possibly consider is that friction discs for a motorcycle may not have the characteristics that are ideal for a kart. The key thing is the difference between static and dynamic coefficient of friction. If that "spread" is too wide, the clutch may tend to "drop-in" a bit much (rpm drop at engagement) and possibly not "unhook" very well as revs drop. Both of those issues can be solved (or "tuned") by adding more spring and more weight, possibly changing material/hardness of floaters, etc., but it could still be something to think about.
It's all tunable with some creativity, no doubt.
Would love to see your design!
PM
Pete_Muller
Moderator
Cool !!
Would you care to share the CAD model so I can see the details? Completely understand if you don't want to.
PM
Would you care to share the CAD model so I can see the details? Completely understand if you don't want to.
PM
Ted Hamilton
Helmet Painter / Racer
Pete -- I'll post more later. But basically, it's an overgrown Bully that operates in "reverse," meaning that the basket is keyed to the axle and the floaters / discs are on a needle bearing sleeve around the axle. Operation is just like a Bully, and if I can manage to make it actuate in the same throw as a Bully, I'll use Bully parts and Harley / Ducati discs. When I have the model resurrected, I'll post back here. It started as a thought exercise, and then I realized that never changing fluid and having easy access to tune it might be nice. However, it IS a lot of spinning parts to beware of... I'm contemplating mounting the 8mm belt drive with the flange shielding the levers...
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Pete_Muller
Moderator
Look forward to see your progress!
Something in your message reminded me of the road race (aka: enduro) kart that Terry Hegar brought to the 1979 Nationals. He was running Open Heavy (single 100cc two stroke, with very few limitations).
What he did was create a 2-speed drive system with two axle clutches. The engine had two belt gears side by side on the extension shaft. On the "lower" gear ratio side, the engine drove the guts to one axle clutch, like normal. The higher (numerically lower) side had the guts of the clutch attached to the axle, and the drum rode on a bearing on the axle and the belt pulley was attached to that drum. There were one or two one-way bearings in the system, but can't remember exactly where (I'd have to sketch it out to jog my memory). These were "shoe" clutches, not disc.
Essentially, the lower ratio did all the "propulsion" until the axle speed got high enough for the shoes to come out and engage the drum on the higher ratio side, at which point that ratio would take over propulsion and the lower ratio side just over-ran (free-wheeled) due to the one-way bearing(s) in the system.
It was *really* clever. I can't remember how he did in that race, but I don't recall him winning. (I tried to find results of the '79 IKF RR Nationals, but can't locate them anywhere). There was probably a bit too much complexity and weight in the system, but super creative for sure. As with everything Hegar: it was beautifully built.
PM
Something in your message reminded me of the road race (aka: enduro) kart that Terry Hegar brought to the 1979 Nationals. He was running Open Heavy (single 100cc two stroke, with very few limitations).
What he did was create a 2-speed drive system with two axle clutches. The engine had two belt gears side by side on the extension shaft. On the "lower" gear ratio side, the engine drove the guts to one axle clutch, like normal. The higher (numerically lower) side had the guts of the clutch attached to the axle, and the drum rode on a bearing on the axle and the belt pulley was attached to that drum. There were one or two one-way bearings in the system, but can't remember exactly where (I'd have to sketch it out to jog my memory). These were "shoe" clutches, not disc.
Essentially, the lower ratio did all the "propulsion" until the axle speed got high enough for the shoes to come out and engage the drum on the higher ratio side, at which point that ratio would take over propulsion and the lower ratio side just over-ran (free-wheeled) due to the one-way bearing(s) in the system.
It was *really* clever. I can't remember how he did in that race, but I don't recall him winning. (I tried to find results of the '79 IKF RR Nationals, but can't locate them anywhere). There was probably a bit too much complexity and weight in the system, but super creative for sure. As with everything Hegar: it was beautifully built.
PM