Clutch actuating mechanism thoughts

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lrutt

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On one hand (left), the diaphragm clutch is great and works well. Good design.

On the other hand (right), could that clutch actuating mechanism be any stranger? without modeling it on a computer it sure seems to be a strange and inefficient design. But I guess it works. Of all the ways I could think to push that rod in, the stock Norton setup would be the last thing I would think of.

Kept thinking of that as I was wrapping up my layshaft bearing replacement last night.

Just a comment
 
lrutt said:
On one hand (left), the diaphragm clutch is great and works well. Good design.

On the other hand (right), could that clutch actuating mechanism be any stranger? without modeling it on a computer it sure seems to be a strange and inefficient design. But I guess it works. Of all the ways I could think to push that rod in, the stock Norton setup would be the last thing I would think of.

Kept thinking of that as I was wrapping up my layshaft bearing replacement last night.

Just a comment
Click to expand...

And the more I look at it... The more intuitively sensible the hydraulic option looks...!
 
lrutt said:
On the other hand (right), could that clutch actuating mechanism be any stranger? without modeling it on a computer it sure seems to be a strange and inefficient design. But I guess it works. Of all the ways I could think to push that rod in, the stock Norton setup would be the last thing I would think of.
Click to expand...
Agreed, but looking at how the cam is shaped, the first bit of travel of the cable causes a proportionately large movement at the pushrod to removed slack from the pushrod, then goes into a relatively slow section to give greater leverage against the diaphragm spring while also contributing to a more "relaxed" grip at full draw. Now, if I can just figure out how to keep the roller from going flat...

Nathan
 
Nater_Potater said:
lrutt said:
On the other hand (right), could that clutch actuating mechanism be any stranger? without modeling it on a computer it sure seems to be a strange and inefficient design. But I guess it works. Of all the ways I could think to push that rod in, the stock Norton setup would be the last thing I would think of.
Click to expand...
Agreed, but looking at how the cam is shaped, the first bit of travel of the cable causes a proportionately large movement at the pushrod to removed slack from the pushrod, then goes into a relatively slow section to give greater leverage against the diaphragm spring while also contributing to a more "relaxed" grip at full draw. Now, if I can just figure out how to keep the roller from going flat...

Nathan
Click to expand...
An old guy told me to lean as far to the right as possible... while stopped in the garage, to lube the shifter and clutch mechanism.
 
Yes that is how the sweet Commando clutcthes feel to me, like a modern compound bow that quickly 'beaks' over most the effort so easy to hold arrow to aim before letting 70lb spring go...

My SV650 has a screw/spiral release that is no easier than a Cdo with decent pack height but wears out faster as its made of stamp sheet metal and a few bb size roller balls. I prefer my Cdo's over other similar power cycles I've squeezed. I must slip clutches a lot to get around here, I find my Cdos easier to hold in just enough slip & not stal while easing out to full engagement than the girlie beginer SV. Its still stumps me why there's so many Cdo clutch force complaints as never have measured anything but sense of how close a fit to get the spring to just fit into its groove easy w/o much space to the plates.
 
I think the clutch system is simple and effective and when setup properly smooth and easy to use. But when there is something wrong, yo know it. I think that this mechanical feedback is critical and a good thing and why I (no offence intended in anyway) am reluctant to use a hydraulic clutch systems.

I know this and the other thread are very alike. I will comment here on this also.
Although the cable can effect lever pull, i think this is a small percentage of why we get hard pull clutches. Clutch pack, clutch centers and actuators play a much higher percentage of a role for the hard to pull clutch.
For this reason the hydraulic clutch could be bad by masking a more serious issue.
A hydraulic clutch is a great thing but may meant for a clutch system that was designed for it.

I think the OEM clutch is good and match the balance of the rest of the bike.
 
Unless you have an over-centering type of lever on a clutch mastercylinder, you will only get a lineal movement and it will be a heavy pull through the whole range. The Norton design has that over-centering design in the gearbox. Perfect when set up to work as it should.
Dereck

ps, amazing, but I have never had a problem with any of my clutches apart from the ones that were "redesigned" by PO's mechanics.
 
At just shy of 13k miles, the stock clutch was starting to slip in 4th gear during any "spirited" acceleration moments. Having already installed a pushrod seal, the plates seemed to be free of tranny lube, so the pack height was check and found to be ~0.040" low. You can see where the pressure plate is receded into the drum.
Clutch actuating mechanism thoughts


It's kind of hard to see, but this shows how far the spring is recessed below the circlip groove.
Clutch actuating mechanism thoughts


Not having different thickness plates available, and, after taking some careful measurements, a shim spacer was built out of 0.040" shim stock. I figured that moving the spring towards the plates was no different than moving the plates towards the spring (it's a mountain/mohammad thing).

Spacer
Clutch actuating mechanism thoughts


Spacer installed
Clutch actuating mechanism thoughts


Holy cow! Now, the clutch spring does its "compound bow break-over thingy", and it's truly a two-fingered affair. Even better, all signs of slippage are gone. I'm a believer!
 
Yeah Man! Yippy Kye Aye! Clever bodge that should last a while too. I've 3 pressure plate thicknesses on hand and couple sets of old/new clutch pack plates to mix and match by mere eyeball till spring just slips in nice for sweet easy clutch action. Cable lube and routing are secondary to stack thickness biggie you solved thinking outside the box.
 
There must be something different between all bikes, because mine has that space and if I remove it, the clutch slips. I live with the space and I still get the 'break over' situation, no slippage and good clutch action. Go figure.

Dave
69S
 
hi , I just made the comment to a supplier last week suggesting that all Commando's are no the same. That was a reference to Exhaust headers.
Dereck
 
True that. I recently set up the clutch in my MK III to Dyno Dave's specs by machining a 750 pressure plate down to the right thickness. I was looking for a lighter clutch pull for my grandson to ride the bike at the Oregon rally, and we did get that. Unfortunately, it also produced a clutch that slipped under hard riding. I've never had a problem with the stock 850 bronze plate clutch on the race bikes, even with 920 engines, but they all had a 1.75 ratio belt primary, which makes life a lot easier for clutch and gearbox compared to the stock 2.19 ratio. I'm planning to go to a taller primary ratio on the MK III during it's rebuild this year (as well as a hydraulic clutch), if I can do so and still keep an electric starter.

Ken
 
lcrken said:
True that. I recently set up the clutch in my MK III to Dyno Dave's specs by machining a 750 pressure plate down to the right thickness. I was looking for a lighter clutch pull for my grandson to ride the bike at the Oregon rally, and we did get that. Unfortunately, it also produced a clutch that slipped under hard riding. I've never had a problem with the stock 850 bronze plate clutch on the race bikes, even with 920 engines, but they all had a 1.75 ratio belt primary, which makes life a lot easier for clutch and gearbox compared to the stock 2.19 ratio. I'm planning to go to a taller primary ratio on the MK III during it's rebuild this year (as well as a hydraulic clutch), if I can do so and still keep an electric starter.

Ken
Click to expand...

I wrote the article... but did not realize there are "specs" to build to. The point being thicker does one thing, thinner does the other.

"You can see using a straight edge on the diaphragm, if it is flat, extended or inverted. It is interesting to note that as the clutch wears, it always gets harder to pull until it finally gets to .40”extended. Then its up to 325lbs of pressure! I don't necessarily endorse this as a must do modification. But you should understand what is happening if you decide to go through with it. The lowered clamping pressure may cause slipping."

With so many opinions about clutch pack combinations, I prefer to stay out of chevy/ford controversies.
However, I did 1/4 mile drag race my belt drive combat with 21T sprocket. I would only fully wind out 3rd gear, never improving by going to 4th at the line. On the street the engine would never over power (47RWHP) the clutch (slip) to max MPH. I tended to ease off at 100 indicated, though there was more potential. I use and prefer the solid fiber plates. YRMV

My MKIII did slip it's stock bronze clutch at 80+... once it eventually got primary oil on the plates. It did take 3-4 seasons after putting a CCRS.
 
lcrken said:
True that. I recently set up the clutch in my MK III to Dyno Dave's specs by machining a 750 pressure plate down to the right thickness. I was looking for a lighter clutch pull for my grandson to ride the bike at the Oregon rally, and we did get that. Unfortunately, it also produced a clutch that slipped under hard riding. I've never had a problem with the stock 850 bronze plate clutch on the race bikes, even with 920 engines, but they all had a 1.75 ratio belt primary, which makes life a lot easier for clutch and gearbox compared to the stock 2.19 ratio.
Ken
Click to expand...

You did right setting up the clutch as per Dyno Dave's specs but you should replace the stock bronze plates for Barnett plates (guaranteed no more slipping). I also replaced the stock actuator for a Dominator actuator and now have an one finger clutch pull :!: Although the Dominator actuator reduces displacement of the clutch rod there still is enough movement to free the clutch from dragging.
 
dynodave said:
I wrote the article... but did not realize there are "specs" to build to. The point being thicker does one thing, thinner does the other.

"You can see using a straight edge on the diaphragm, if it is flat, extended or inverted. It is interesting to note that as the clutch wears, it always gets harder to pull until it finally gets to .40”extended. Then its up to 325lbs of pressure! I don't necessarily endorse this as a must do modification. But you should understand what is happening if you decide to go through with it. The lowered clamping pressure may cause slipping."
Click to expand...

Dave, I didn't mean to imply that you had given a specific dimension the clutch should be set up to. In my world, numbers that specify the dimensions, spring rate, or other performance parameters of a device or system are called specifications, or more simply "specs". That's what you provided, and I used it as a guide to lightening the clutch pull. You did indeed warn that it might cause slippage, and I wasn't all that surprised that it did. No criticism intended, just passing on my experience with the process.

Another caveat, and then I'm done. I'm not criticizing the Commando diaphragm clutch design. I think its a clever design compared to the older coil spring units, and I like it a lot. Properly set up, it does reduce the force at the lever required to hold in the clutch, while still providing sufficient force on the plates when closed, which isn't the case with the coil springs. It would be even better if we could lighten it up a bit, as well as fitting a couple additional plates to increase its torque capacity, but that's another thread for another day.

Ken
 
I got the thick light weight Aluminium hard anodized pressure plate form RGM. It was a little too think and needed to be faced off a bit. The trouble is that I really wanted to retained the hard anodized face toward the clutch action.

So I had to fiddle with the contour of the raised outer portion that contacts the diaphram.
No big whoop, just not all that staight forward of a procedure.
 
lcrken said:
dynodave said:
I wrote the article... but did not realize there are "specs" to build to. The point being thicker does one thing, thinner does the other.

"You can see using a straight edge on the diaphragm, if it is flat, extended or inverted. It is interesting to note that as the clutch wears, it always gets harder to pull until it finally gets to .40”extended. Then its up to 325lbs of pressure! I don't necessarily endorse this as a must do modification. But you should understand what is happening if you decide to go through with it. The lowered clamping pressure may cause slipping."
Click to expand...

Dave, I didn't mean to imply that you had given a specific dimension the clutch should be set up to. In my world, numbers that specify the dimensions, spring rate, or other performance parameters of a device or system are called specifications, or more simply "specs". That's what you provided, and I used it as a guide to lightening the clutch pull. You did indeed warn that it might cause slippage, and I wasn't all that surprised that it did. No criticism intended, just passing on my experience with the process.

Another caveat, and then I'm done. I'm not criticizing the Commando diaphragm clutch design. I think its a clever design compared to the older coil spring units, and I like it a lot. Properly set up, it does reduce the force at the lever required to hold in the clutch, while still providing sufficient force on the plates when closed, which isn't the case with the coil springs. It would be even better if we could lighten it up a bit, as well as fitting a couple additional plates to increase its torque capacity, but that's another thread for another day.

Ken
Click to expand...

A trick I use to get more clutch bite when you have plenty of pushrod travel -like with a hydraulic clutch -is to thin the pressure plate by removing material from the spring side. When doing that you can move the spring contact point out about 3/16 inch which will increase the leverage of the diaphragm and squeeze the plates considerably tighter. Jim
 
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