Nev's Lock Up Clutch

warp9.9 said:

The heavier springs are used because the bike has so much low end torque the clutch would start to slipp before the bearings could do their job. These test were on a High compression Rocket Nev biult.

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So with the heavier springs it locks up sooner, would it also force the bearings back in sooner?

Never mind I reread this thread for the third time and I think I answered my own question.

I wonder if steeper and shorter ramps would make it lock and unlock sooner?

Is there any concern with having a steel bearing exerting pressure on the aluminum inner clutch head?

Haaa... I think I'm getting my head wrapped around this, so to speak. This is all good stuff, and Warp's input is helping a great deal. I understand how the clutch works... and I may even understand the laws of physics that apply to this and how they might effect it's operation. I have to go to work but tonight I'll post up a plan I have (maybe two) and you guys can tell me what you think.

Murray will have to answer that but IMO because the aluminum pressure plate has been milled will a ball end mill the radius of the bearings transferring pressure around about half the hemisphere of the bearing this reduces or from what I have seen eliminates the load on one spot on the bearing and this is why it does not Gaul the aluminum tracks. I have noticed a little bit of markings on the stationary steal head but nothing detrimental when I open mine up I will take some pictures. These markings lead me to believe there is not much more travel left on the balls so if you add more shims you might run out of track for the balls and loose the lock up action. any less shims and you reduce clutch head movement and the clutch will lock up faster.

I hope I am not babbling to much I ran into problems installing mine (Not Nev’s fault just needed to set it up right and the clutch is fine)

IMO the lock up clutch is not for everyone and with out upsetting Hombre or Nev I am suspecting if you are not a extreme rider and do not reach the HP areas Walt is operating in and you don't drag race you might get away with just heavier springs. I am just guessing that most clutch slippages happen on the dyno when the rear wheel is sucked down to the eddy brake wheel and if you think of the force/loads happening on the dyno by the eddy brake you would have to lower your tire pressure to get the same amount of wheel surface contact/grip and loads that is seen on the dyno to get the same load on the road. With a fully inflated motor cycle tire you don't have the surface contact with the road there fore you might end up spinning the tire first before you slip the clutch. ( I am just pondering this idea though and not taking into mind the Dark side riders who might have more traction from rubber contact with the road) I also think that the lock up clutch without the bearings and having stronger springs will grip more the standard clutch with stronger springs due to the pressure plate (movable clutch head) being thicker and therefore not flexing as much as the stock one can. Let me reiterate I am just thinking about this I am know engineer and I have Nev's clutch and will not go back. But I do ride extremely hard all the time the bike makes me do it When I went back in to see if I could figure out why I was breaking **** I did make some changes (adjustments) I figured with tolerances on machined parts some thing was not totally aligned and I found that the back of the lifter piece did not come out far enough so the fingers on the lifter shaft when parallel ( just before it would grab the lifter piece were not in the same location) and then if you add the .0015" cover gasket they were more out of machined alignment. So I surface ground the spacer the lifter piece set in and moved the back of the lifter piece foreward .005 past the lifter shaft fingers when they were parallel which gives me .005 clearance right before contact happens. So far so good!!!!!!

Oh and just so everyone knows shifting without the clutch lever at low rpms is a breeze. Just as easy as using the clutch lever a little more practice at higher rpms but not hard at all of course you all should realize when thrashing her hard the only thing left to absorb shock is the springs on the back of the basket and one of our Captains has detonated his clutch basket and you can see the damaged springs.
As Hombre said it’s a trade off you must make when exploring the high HP range. Like changing the tune your gas mileage gets worse if you trying to release more power
All and all I love this beast and I am not mad I break **** horsing around. I have never had the head off but am actually looking forward to taking a peek at her insides.

Again I must say I am no engineer and am waiting for Murray to chime in so if you do not agree with my opinion that's ok with me and if you have some other ideas I would like to hear them because it helps me think of what is going on inside my girl and you all know women are hard to figure out. By the time you figure a woman out you will be six foot under and well then it really don't matter

Oh just so you all know the .100 movement of the clutch head is roughly calculated to about 25 degrees 4 minutes and 12.82 seconds of the lifter shaft rotation to reach the full head movement. keep in mind tolerances+ - do change things a little.

here are some pictures of Brembo's clutch basket that failed.
I also found that the pazzo adjustable levers give more adjustment then the stock ones this will aid in adjustment to eliminate clutch head over pull which breaks lifter shafts also.

NOTICE the oil pump drive chain in the top picture did not fare out well either!

This is good stuff . I'm with the Warp Man also when I say I'm not after Nev (or Walt) on this deal.... I just want to play with it some and very possibly I might get it to work more like I want it to. I'm not so gung ho race happy like some of you guys however I'll bet I can fine tune it some so I'm happy with it. You have to keep in mind that my bike is probably making about 155 RWHP right now and we have an appointment to get a dyno session on April 4th, so we will have a better idea of where we are at in that department.

Here are some bizzare theories I have... tell me what you think. These are just me tossing some ideas around so they may be completely wrong and don't be afraid to rip them apart.

I'm beginning to think that the ball bearings traveling a long way (or all the way) up their ramps to the outer edge of the pressure plate may make it harder to force the bearings back into the middle so that the clutch will release. Here's why:

Lets say the engine is running and we have locked the throttle so that it is turning a constant 1000 rpms (in this example I just don't want the rpm's to vary, I'm not worried about the clutch locking up) and the transmission is in nuetral. In our lock up clutch pressure plate, let's say the balls start out in the center, close to the release rod. The balls are now travelling around in a circle and using the Pie R Squared formula where R is 1 inch those ball bearings are travelling 3.14 inches for each revolution of the pressure plate. Lets say we now move the ball bearings out 1/2 of the way up the ramp and that R is now 2 inches. Now the ball bearings must move 12.56 inches for each revolution. Now lets move them all the way out to the end of the ramps and lets say that this is 3 inches. (I am just making these values for "R" up, I didn't measure them. this is just for making an example). Now the ball bearings must move 28.26 inches for each revolution of the pressure plate.

So now we have three distances that the ball bearings must travel:

R= 1" 3.14
R= 2" 12.56
R= 3" 28.26

So at a constant 1000 rpm's, the farther out the ball bearings are the faster they have to travel, in other words, they have a greater velocity.

From my High School Physics class I seem to remember a few things. One was that there is really no force called "Centrifical Force". It is rather something called "Moment of direction". This simply states that a given body wants to travel in a straight line. This simply means that if one of our ball bearings was to come loose from the pressure plate it would fly off on a straight line path (and probably hit me between the eyes). This is the force that pushes the ball bearings to the out side of the pressure plate.

Also most "force" (or energy) is defined as mass times velocity. So something that has a constant mass (like our ball bearings) will store more energy if it is travelling faster. Please refer to my little distance chart above and think about the velocities the ball bearings must be travelling in the different positions.

Soooo... to push those ball bearings back inwards down the ramps it would be easier to do so if they weren't so far out. Therefore if the pressure plate is in lock up mode I might be able to easily unlock it (force the ball bearings in) if they locked more twords the center than the outside of the pressure plate. And if I can unlock the pressure plate I would be able to shift.

This would take away some of the lock up force exerted by the ball bearings. I may be able to compenstate for this by using heavier clutch springs. The clutch will also lock up sooner, this may not be an issue in real world useage, I would probably just "get used to it"

So am I correct in thinking in order to limit the travel of the ball bearings you use thinner shims?

Fire away boys

I have another theory also but that last one gave me a headache so I'll post the second one after you guys tear this one apart...

Not bad I should have said centifugal expansion not force. Force is aplied when the can't expand out anymore. Do you think they should grip when they are over the friction disc cause if you want to try this you can take a shimm out. But then will the alluminum plate flex since your applying pressure before the balls are over the friction area of the disc. Will shortening there ability to travel out also cut down on clutch head movement taking a shim out so to speak will not allow the lifter piece to come out as far ? If this happen what about clutch lever overpull flexing the lifter shaft and snapping it (I have broke one by overpulling the travel of the clutch pack!)
I am presently on my third lifter shaft good thing I have one or two more on the shelf

I do like your thoughts!!!!
Well I better get off my lazy arse and start pealing my head so I can observe a moment of silence for my broken rings/possibly pucked up pistons and ****.
a product of detination at high boost **** the luck
Time for intercooling to be added $$$$$$$$$$$$

Shims have nothing to do with it... having shorter "ramps" for ball bearing travel will limit the lock-up force applied. Your centrifugal force operational theory is correct, and idea of "un-locking" sooner would be correct for shorter ramps. However, you may find that shortening the ramps weakens the "lock-up force" enough to make the clutch ineffective, and no better than a stock clutch with stronger springs.

To mutch lockup

warp9.9 said:

Not bad I should have said centifugal expansion not force. Force is aplied when the can't expand out anymore. Do you think they should grip when they are over the friction disc cause if you want to try this you can take a shimm out. But then will the alluminum plate flex since your applying pressure before the balls are over the friction area of the disc. Will shortening there ability to travel out also cut down on clutch head movement taking a shim out so to speak will not allow the lifter piece to come out as far ? If this happen what about clutch lever overpull flexing the lifter shaft and snapping it (I have broke one by overpulling the travel of the clutch pack!)
I am presently on my third lifter shaft good thing I have one or two more on the shelf

I do like your thoughts!!!!
Well I better get off my lazy arse and start pealing my head so I can observe a moment of silence for my broken rings/possibly pucked up pistons and ****.
a product of detination at high boost **** the luck
Time for intercooling to be added $$$$$$$$$$$$

Click to expand...

WELL GUYS we are using heavy springs with no problems at all . we dont like to use lock ups on the street
because of these related problems when we do we use heavy springs and the least amount of lockup possible so it only comes into play at higher rpm and you can still pull the clutch lever in at normal cruising rpm and you shouldnt be riding with low tire pressure on the road it ruins the handling - let the tire spin some it will keep the front end from lifting - your breaking the hubs because there is no give whatsoever in the drive train- to mutch lockup on the clutch - we have had these problems in the past

Well... See... There's something I didn't think of. But, at what position do the ball bearings actually lock up at now? Do they go all the way to the end of the ramps? Or does it lock up before that? (And that may vary by bike). Plus, on the stock clutch the springs exert the clamping force and they are in the middle of the pressure plate, not over the clutch plates. so maybe in practice where the ball bearings end up may not be an issue as it relates to being located over the clutch plates?

Also I'm thinking that just a little less ball bearing travel may reap great benefits in shifting. I'm not talking about limiting the travel dramatically. As you can see by the chart just a little change in "R" results in a big change in velocity.

Also... I am being selfish here because someone like Hombre may want all the lock up he can get. Conservatively he probably is making more than 100 RWHP than I am. If his lock up clutch slipped he may want more travel up the ramps so it locks harder. It may turn out even if I dramatically limit the lock up force by restricting ball bearing travel it still may be more than my bike could currently break loose at 155 RWHP. In practice... for my bike.... I might be able to get better shifting and still have it lock up like two dogs. The way it is set up now I may have the capacity to lock up 300 plus horsepower and I just don't need that. What if we could get it down to the point that if your bike makes 175 RWHP or less you use this size shim, If it makes 200 RWHP you use this size shim and so on?