So I was sitting around and my ADD was kicking in and got me thinking about about racing. Watching a recent movie I picked up "fastest" I saw the bikes squirming coming into corners. I know our bikes are older, and slipper clutches were not an option during that period, however I also noticed the hogslayer had a slipper clutch installed. So has anyone though of trying to make their own? I noticed none of the racing nortons I have seen use one, or anyone in the vintage class for that. See what happens when I start thinking...
Slipper clutch
- Thread starter Vulin
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I got ym own sepcail case of ADD and want nothing to do with no slipper clutch which is for sissies that either can't brake upright in time or their steeds can't take any power all the way into though and out of turns, chicanes and sweepers. Its stupid and foolish to use engine to brake anyway as rear gives such low drag compared to the front. Besides our Norton got real nice heavy energy storing power delivery dampening flywheels so are not at same risk to just snatch out from under on power left offs. The other issue is these slipper clutch buzz bombs are getting power by hi rpm not pure torque so they are geared down which makes their engine drag more dramatic than out beasties. An another thing them anger plastic looking insects all float around on balloon like tires that are cat's meow to mostly upright heat handling on patch very similar in area to our skinny ones but boy howdy do them balloons get squirely faster leaned than our more canoe like profiles.
But if you think engine drag is limiting your corner security then I always encourage all extremes of experimentation so hope responses are more useful than mine.
But if you think engine drag is limiting your corner security then I always encourage all extremes of experimentation so hope responses are more useful than mine.
Ron L
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Vulin said:
Errr...it's a whole different definition of "slipper clutch". Drag racing clutches are designed to slip when the clutch is engaged and then lock up as the vehicle gains momentum and moves down the track. On Hogslayer I believe this was accomplished with specially designed fingers which increase pressure on the pressure plate due to centrifugal force. This was common practice on many dragsters and funny cars of the era. Today I expect there is more sophistication, but the same general idea.
On road racing motorcycles, a "slipper" clutch is more of a one-way clutch, allowing the clutch to freewheel when the clutch baskets speed is greater than that of the clutch hub. This prevents the rear wheel from breaking traction due to downshifts.
In any event, I doubt that vintage class racing would allow such modifications. Many classes do not allow floating disc rotors or even disc brakes if they are not period.
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Heinz Kegler (RIP) designed what was essentially a "slipper clutch" when he worked for Norton. Think stock Norton clutch basket teeth cut on a spiral. Simply everthing would tighten up under torque-loosen under downshift. When I raced AHRMA at Sandia, NM, Heinz would pull up a chair at my pit and hang out for hours. I think he was always amazed that I raced a Commando because in his mind a "true Norton" was a featherbed. Anyway he kind of adopted me when I was there racing and we'd go to dinner and spend time in his home shop BS ing about Nortons The fact that he cut the splines on a non CNC mill was pretty impressive. He only built a couple sets-one on a Commando somewhere an the one at his shop. When he worked at Norton he said he demonstrated how well it worked by putting the front wheel against the factory building and smoking the rear tire. Quite a brilliant engineer.
Cheers,
Tom Kullen
Event Coordinator
Bonneville Vintage GP
AHRMA 44x Formula750/BEARS
2010 AHRMA Sportsmen of the Year
http://www.bonnevillevintagegp.com
tomkullen@bonnevillevintagegp.com
Cheers,
Tom Kullen
Event Coordinator
Bonneville Vintage GP
AHRMA 44x Formula750/BEARS
2010 AHRMA Sportsmen of the Year
http://www.bonnevillevintagegp.com
tomkullen@bonnevillevintagegp.com
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utahnorton said:
yes - what a good ole boy Heinz was - truly missed
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Tom, I have the only "slipper" hub that Heinz made.
I live in Albuquerque and was very close to him and his wife, Karen.
Heinz used my Commando as his "test mule" for many of his innovations, including I have his first set of swing arm rings still on my bike.
Heinz used one of my old Commando clutch hubs and milled the driven sides off each spline at 90 degrees so they would, as you say, lock up.
Once assembled, the action was a delight, but was strictly experimental.
What happened was that after about six months in use the male splines of the driven clutch friction plate wore away to nubbins, and because there was nothing left of them, they just spun around the hub! In theory, Heinz's idea was great, but the clutch plate friction splines are too soft and are cut at the angle that interferes with Heinz's 90 degree hub cuts.
I still have that slipper hub, but have had to revert back to a new stock hub and new friction plates.
I have so many wonderful memories of Heinz.
I remember when Brian Tyree invented the pre Mark 3 threaded isolastics, he patented them and took one to Mick Hemmings while in England and they agreed to market them through Mick.
Well, again, my Commando was the test mule for the first set of these, I still them on my bike!
Heinz was indeed a featherbed man, and he would refer to Commandos as "limping camels"
and he would limp around his garage, emulating the gait of a rubber mounted swing arm.
God, how we laughed together at this!
I live in Albuquerque and was very close to him and his wife, Karen.
Heinz used my Commando as his "test mule" for many of his innovations, including I have his first set of swing arm rings still on my bike.
Heinz used one of my old Commando clutch hubs and milled the driven sides off each spline at 90 degrees so they would, as you say, lock up.
Once assembled, the action was a delight, but was strictly experimental.
What happened was that after about six months in use the male splines of the driven clutch friction plate wore away to nubbins, and because there was nothing left of them, they just spun around the hub! In theory, Heinz's idea was great, but the clutch plate friction splines are too soft and are cut at the angle that interferes with Heinz's 90 degree hub cuts.
I still have that slipper hub, but have had to revert back to a new stock hub and new friction plates.
I have so many wonderful memories of Heinz.
I remember when Brian Tyree invented the pre Mark 3 threaded isolastics, he patented them and took one to Mick Hemmings while in England and they agreed to market them through Mick.
Well, again, my Commando was the test mule for the first set of these, I still them on my bike!
Heinz was indeed a featherbed man, and he would refer to Commandos as "limping camels"
and he would limp around his garage, emulating the gait of a rubber mounted swing arm.
God, how we laughed together at this!
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So you have the original test set! Was wondering how they would hold up in the long haul but I was strictly interested in racing. I use Mike Barnett's aluminum clutches so if they would have lasted a weekend of practice and racing that would have been fine but sounds like the the aluminum teeth might not last the weekend?? I guess if there were a demand you could cut the discs out with a CNC laser and set up a machine jig to grind the correct angles. I do know there is one other of Heinz's slipper clutches floating around somewhere as he showed it to me at his house. He said the other was running around on another Commando-yours! Since he wasn't interested in going into production I asked if he was interested in a royalty sale deal but he was afraid UPS would loose his "only other one" when I shipped it back to him. Instead he sent me photos-but those I think are on one of my old laptops. Might have to see if I can find it- providing it still works... I do have a set of his swing arm clamps on the Stealth Canyon Racer :shock:
Cheers,
Tom Kullen
Event Coordinator
Bonneville Vintage GP
AHRMA 44x Formula750/BEARS
2010 AHRMA Sportsmen of the Year
http://www.bonnevillevintagegp.com
tomkullen@bonnevillevintagegp.com
Cheers,
Tom Kullen
Event Coordinator
Bonneville Vintage GP
AHRMA 44x Formula750/BEARS
2010 AHRMA Sportsmen of the Year
http://www.bonnevillevintagegp.com
tomkullen@bonnevillevintagegp.com
Hortons Norton
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Didn't get to know him as well as some of you, but he was always very willing to spend time on the phone and explain things. I have a way of asking way too many questions and he always had time, Nice guy.
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Hogslayers was a ' SLIDER " clutch . Self engageing so she stays on the boil , not the overun type .
For someone who just doesn’t understand completely the whole technical aspects of this clutch, does the clutch cage/basket have to be straight cut for the clutch tabs or at an angle like the clutch centre?lcrken said:Picture of Heinz' helical clutch, but not the Commando one. Credit for this pic goes to Ben Gradler, who knew Heinz, and sent it to me a few years ago.
Ken
madass140
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In my opinion they would need to be straight cut, standard. the concept is good but I dont believe this set up wouldnt last very long, the reason being the tangs and hub would wear as fast or faster than the straight cut set up. mavbe good for race track with constant rebuilds. just my opinion.
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madass has got it right
my Heinz cut Commando hub was strictly experimental, and it quickly wore the male tangs out of the Barnett friction plates
Both the clutch hub and the friction plate tangs must have the same angled cuts so they can release freely
my Heinz cut Commando hub was strictly experimental, and it quickly wore the male tangs out of the Barnett friction plates
Both the clutch hub and the friction plate tangs must have the same angled cuts so they can release freely
See how the ring Heinz made was welded onto this old hub.
The Domi clutches were made at AMC in the early sixties and Heinz tested them over here for them, he said they were supposed to be incorporated into the experimental DOHC Norton that had an "electra" looking bottom end. But AMC was on the ropes, the DOHC engine turned out to be a total POS, and the projects were axed. Of course Heinz was in the position to adopt old experimental and racing parts and the Domi clutches ended up with him. The Domi clutches were made well, I used one in a 650 for a dozen years or more and it still looks great. It does work very well as a slipper, when you chop the throttle going down a hill or in a low gear you can feel it let go.
A lot of people may not know that the experimental DOHC was shipped over and tested in the USA. Heinz put miles on it and tried to keep it running but it had so many design and reliability problems that it just was not viable for production.
Heinz said that because the splines on the Commando clutch were not square that under torque they bind. Just one more part of the Commando he did not like, but it was his job to solve problems for Berliner and Norton within the constraints of budget and company politics and he did this well and he kept on doing it even after there was no more Norton to work for, he was working in his shop until the very end.
The Domi clutches were made at AMC in the early sixties and Heinz tested them over here for them, he said they were supposed to be incorporated into the experimental DOHC Norton that had an "electra" looking bottom end. But AMC was on the ropes, the DOHC engine turned out to be a total POS, and the projects were axed. Of course Heinz was in the position to adopt old experimental and racing parts and the Domi clutches ended up with him. The Domi clutches were made well, I used one in a 650 for a dozen years or more and it still looks great. It does work very well as a slipper, when you chop the throttle going down a hill or in a low gear you can feel it let go.
A lot of people may not know that the experimental DOHC was shipped over and tested in the USA. Heinz put miles on it and tried to keep it running but it had so many design and reliability problems that it just was not viable for production.
Heinz said that because the splines on the Commando clutch were not square that under torque they bind. Just one more part of the Commando he did not like, but it was his job to solve problems for Berliner and Norton within the constraints of budget and company politics and he did this well and he kept on doing it even after there was no more Norton to work for, he was working in his shop until the very end.
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Saving crashes on motor seizures is a good usage that developed later and
not totally pilot cutting throttle use related but that's not how they got introduced to cycling....
http://en.wikipedia.org/wiki/Slipper_clutch
Slipper clutches were introduced in the 1970s by John Gregory and TC Christenson on "Hogslayer" the most successful drag racing motorcycle of the 1970s. Made of bronze sintered plates from an earthmover and a Rambler 2 speed transmission, the drivetrain let TC reach 180 mph in the quarter mile. Slipper clutches are used on many current sport bikes.
not totally pilot cutting throttle use related but that's not how they got introduced to cycling....
http://en.wikipedia.org/wiki/Slipper_clutch
Slipper clutches were introduced in the 1970s by John Gregory and TC Christenson on "Hogslayer" the most successful drag racing motorcycle of the 1970s. Made of bronze sintered plates from an earthmover and a Rambler 2 speed transmission, the drivetrain let TC reach 180 mph in the quarter mile. Slipper clutches are used on many current sport bikes.
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