My Hydraulic Cluch Conversion

I have been working on this for a while, now on version three! I have a viable working solution.
I know we can buy Jim's excellent system from the show pony stores and there are those out there with superlight two finger cable clutches (Hulk Hogan and Rambow;0) however my 75 mk3 clutch just felt like you were squeezing a turd through a sieve :shock: even with a new hub good bronze and steel plates, stack height checked, and a new well lubed cable it was hard work and in traffic it got dammed painful , what follows is how I have worked my way through the problem.

Version 1

Version one was a remake of the Christmas cracker quality Hydraulic cable type cylinders sold on ebay for peanuts I bought two from China just for the seals , none of the Chinese units had enough travel to fully disengage the clutch, on my MK3, I needed 18mm of cable travel to get 3.5mm of lift on the spring. I made longer cylinder bodies in stainless steel, messed around with piston sizes, and master cylinders, finally I got the system to work but it was heavier to operate than the original cable system I threw that one into must try harder section and went back to the drawing board (sketch pad)

Version 2

Version two had to fit inside the gearbox outer cover and apply direct pressure on the end of the clutch push rod, I had planned to carry out the lay-shaft roller bearing conversion and replace the bushes in the rest, so decided to combine the two jobs while I was in there. I worked on making a cylinder that would fit inside the covers and not affect the workings of the gearbox ratchet mechanism now it's done and working thought I would share it.



Version 3
Hard anodised and ready for use





All installed and working fine



Still a few things to finalise however It's lighter than the cable mechanism to operate, gear changes are more positive and finding neutral is no longer like searching for a lost tribe in the Amazon rain forest :wink:

slick!

the pictures don't show all the details, how do you bleed it?, and what dia of piston is required at the left handle bar?

how do you bleed it?, and what dia of piston is required at the left handle bar?

Click to expand...

14mm works well 5/8 is better (XJR1300) as for bleeding the system, the at the moment I vent at the hose unions,

loosen the bolt, squeeze the lever, tighten the bolt, release the lever, and repeat once the hose and the slave cylinder are full short pulls on the lever brings the rest back up into the master cylinder, with the translucent hose (1/4 rocker oil feed hose) you can see it all happening live . I will eventually fit a braided line and use a banjo bolt with the bleed nipple in the end.

Esmerela said:

I have been working on this for a while, now on version three! I have a viable working solution.
I know we can buy Jim's excellent system from the show pony stores and there are those out there with superlight two finger cable clutches (Hulk Hogan and Rambow;0) however my 75 mk3 clutch just felt like you were squeezing a turd through a sieve :shock: even with a new hub good bronze and steel plates, stack height checked, and a new well lubed cable it was hard work and in traffic it got dammed painful , what follows is how I have worked my way through the problem.

Click to expand...

A beautiful piece of work.

I will say that if you're stock clutch was too stiff you had some problem you hadn't addressed.

Stack height is not easy to get right. But when you do it's magic.

That's pretty nifty, but it will conflict with the linkage for rearset controls if part of the same bike.

I will say that if you're stock clutch was too stiff you had some problem you hadn't addressed.

Click to expand...

Quite possibly the case, however my riding buddy has a 77 MK3 and that has a heavier pull than mine was. I presume that because the MK3 had the highest lift clutch operating lever of all the Commandos it would be the heaviest to operate.

That's pretty nifty, but it will conflict with the linkage for rearset controls if part of the same bike.

Click to expand...

Agreed, my system in it's present form is not suitable for a RH change bike if it has rearsets , I plan to move the feed connection inboard by about 10mm when I swap over to a braided line, that will still leave enough room to rotate the inspection cover for oil changes, I only had my Mk3 to use as a reference for fit and functionality. I did experiment with the banjo fitting bolted directly to the side of the slave cylinder taking the flexible hose through the inspection cover, but that required a vent to purge the air from cylinder.

Esmerela said:

I will say that if you're stock clutch was too stiff you had some problem you hadn't addressed.

Click to expand...

Quite possibly the case, however my riding buddy has a 77 MK3 and that has a heavier pull than mine was. I presume that because the MK3 had the highest lift clutch operating lever of all the Commandos it would be the heaviest to operate.

Click to expand...

The operating lever 06-0715 was the same for all Commandos from '68, although the diaphragm spring was apparently increased in strength twice without any change of spring part number, however, I believe that occurred before the Mk3.
Cable type(lined), correct routing and careful attention to the stack height will often lighten the clutch pull.

With a cable operated clutch, the dimension between handlebar lever pivot and nipple needs to be 7/8" generally it's 1" on lucas levers. Esmerela says she has done all the good things in the original post. Amal levers are 7/8" but don't cater for the switchery

gripper said:

With a cable operated clutch, the dimension between handlebar lever pivot and nipple needs to be 7/8" generally it's 1" on lucas levers.

Amal levers are 7/8" but don't cater for the switchery

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I wouldn't necessarily agree that the pivot radius "needs" to be 7/8" (standard is 1-1/16") or any need to change to an Amal 7/8" pivot lever as the pull force required also depends on the ratio of the lifter mechanism inside the gearbox which can also be changed, either by altering the lifter profile or by fitting an 'Atlas' lifter arm, however, the trade-off for a lighter clutch action in both instances (and possibly also a hydraulic lifter) will be some loss of clutch lift.


http://atlanticgreen.com/ndnsclutch.htm
'Atlas Actuator'