Clutch Diaphragm

Hi All
Does anybody know of a clutch diaphragm available that will make the clutch more user friendly on my MKIII Interstate, all the obvious things have been checked cable and all other bits lubricated , someone at a recent V.M.C.C club meeting let me try their MKII it was as easy as the one on my venom two fingers....

Whether your clutch feels light or heavy depends greatly on the clutch plate stack height adjustment and also cable routing [Edit: and lifter mechanism], and not the diaphragm itself and no-one makes an alternative spring as far as I know, although the early clutch diaphragms had a lower spring rate apparently,-even though the part number never changed?

Not-Ron

If you've done the above and it is still too hard to pull then you may want to look into the hydraulic kit designed by Jim Comstock.

Scooter

I v'e had the clutch out and checked the stack height everything is as it should be I used Dave Comeau web page for reference, I have the clutch rod oil seal fitted but suspect that there is still some contamination occurring because the clutch is dragging when changing up or down buit not when stationary !!. I have just looked at Norvils website and they say that this is a problem with the sintered bronze plates and recommend using Surflex plates instead.......anybody tried this and was it successful ?? :!:

I too have the stiff clutch pull syndrome.
Properly Routed Venhill Nylon Lined Cable.
Stack Height is full right up to the circlip no room for a shim.
Actuator positioned as in pictures posted in the many other threads.
My CTS (Carpal Tunnel Syndrome) is really acting up when I use this bike.
The CNW Hydrolic Clutch upgrade is a pricey fix ($459 + shipping)+ Install.
But if it really realy does away with the stiff pull and solves the problem then I will consider it.
Readers of this post please chime in:
I had a stiff 5 finger clutch pull and now with the CNW Hydaulic Clutch its a 2 finger?
Can you say this? Or is it something else?
Thanks in advance.'
J dog

have you checked the clutch centre splines for slot wear? This is a real contributor to plates not freeing up smoothy and also to a jerky action. Replacing the centret will show an immediate improvement. Also, if you do renew it, beware the new one may have insufficient clearance where the rear face abutts the inside of the clutch basket bearing boss. A gentle grind around the inner flange of the centre will obviate any contact and subsequent dragging.

Mick

Open the gearbox inspection cover and make real certain that the clutch rod arm the cable attaches to has not
"fallen". This is a very common cause of stiff clutch feel. Seriously, check this first.
If you do not fully understand this concept, ask.

You mean it should look like this?


And the basket should be full like this?


I'm stll wondering if the CNW Hydraulic Clutch upgrade will fix the stiff pull action?
And compensate for proper actuator positioning and no room for the popular shim fix.

J dog

Surfdog said:

I too have the stiff clutch pull syndrome.
Properly Routed Venhill Nylon Lined Cable.
Stack Height is full right up to the circlip no room for a shim.
Actuator positioned as in pictures posted in the many other threads.
My CTS (Carpal Tunnel Syndrome) is really acting up when I use this bike.
The CNW Hydrolic Clutch upgrade is a pricey fix ($459 + shipping)+ Install.
But if it really realy does away with the stiff pull and solves the problem then I will consider it.
Readers of this post please chime in:
I had a stiff 5 finger clutch pull and now with the CNW Hydaulic Clutch its a 2 finger?
Can you say this? Or is it something else?
Thanks in advance.'
J dog

Click to expand...

What is your actual stack height?

If it's within the specs then I'd try the Atlas actuator first. Then go for the hydraulic clutch.

Another variable in regard to how easy a clutch is to pull in is the distance between the pivot of the clutch lever and the centre of the cable's nipple. From memory on Dommies this distance is 7/8", while on very similar Doherty levers used on Triumphs its about 1" or 1 1/8". It doesn't sound like much, but it makes a surprising amount of difference to the effort required to pull the clutch in.

So are Surflex clutch plates the resolution to this problem ?....I will check the actuator arm and the clutch basket is as pictured above.......when I originally bought this bike it had issues with the clutch and I discovered that it had an extra steel plate,since this has been removed it has improved but there is still the issue with it hanging on between gear changes and the heavy pull...I think it is the oil migrating from the gearbox because the problem is worse when the clutch gets hot. One consideration is that the bike is left on it's side stand and as it's not used through the winter I wonder if this causes the oil to migrate through to the clutch knowing the sintered bronze plates absorb the gear oil and then discharge it when hot it seems to me the that an alternative clutch plate might at least resolve half the problem !

not-ron said:

So are Surflex clutch plates the resolution to this problem ?....

Click to expand...

No. Clean sintered bronze plates drag less than any of the fiber plates.

I will check the actuator arm and the clutch basket is as pictured above.......when I originally bought this bike it had issues with the clutch and I discovered that it had an extra steel plate

Click to expand...

The extra plate sets the diaphram spring out further, which reduces its tension. The difference in clutch pull with/without that plate should be dramatic. If not, something's wrong.

So are we saying there will be less drag with the extra plate in ? In the mean time I have stripped the clutch and found that one bronze plate and one steel plate were stuck together I think that this is an issue with oil seepage as the clutch rod seal had undone itself from the shaft , I can live with the clutch being heavy but not with the bad gear changing antic's so I'm going to refit the seal on the end of the shaft put in a new "O" ring and see what transpires.

bsaboss said:

Another variable in regard to how easy a clutch is to pull in is the distance between the pivot of the clutch lever and the centre of the cable's nipple. From memory on Dommies this distance is 7/8", while on very similar Doherty levers used on Triumphs its about 1" or 1 1/8". It doesn't sound like much, but it makes a surprising amount of difference to the effort required to pull the clutch in.

Click to expand...

Amen to that. Even without adjusting my clutch stack height, I managed to go from having a heavy clutch action to a reasonable one with the original clutch lever perch, a new cable that I spent ages routing for the optimum pull, plus a new actuator arm. Also, cables differ. I made up my own nylon-lined one from a Venhill kit and it contributed to a heavier action than a new one from Norvil. Commandos also seem to be very sensitive to cable length. Too short = heavier pull.

I had some drag when the clutch was not adjusted properly. You must slacken off the cable at the handlebar fully, then screw in the adjuster on the diaphragm until it meets resistance and then slacken off half a turn or so. You then take advantage of optimum lift and lever effort. And, unless your plates are uncontaminated by gearbox oil, you will have that annoying drag and poor gear changes.

I visited Matt at Colorado Norton Works last weeks and he suggested I pull the lever on a Commando he had just install led the hydraulic clutch on, it was marvelously light, wonderful.
I cannot tell from your picture where the clutch rod arm is.
I would loosen the cable at the lever end and then disconnect it from the gearbox end in order to grab a long nose pliers and pull gently towards you and then up to feel the lever arm's movement to insure it stays in the most up position when you reattach the clutch cable there. Is your cable itself nice and lubes, I bought a teflon lined cable recently and that also makes a nice difference. Also, take all the plates out and clean them and a lll the splines with degreaser.
Let us know!

Another possibility for heavy clutch action and drag is that your primary chain (or belt) is too tight. Read the tech digest for proper adjustment and be sure the chain is truly slackened off before obtaining the appropriate movement. Can make a world of difference, not to mention the reduction in wear and tear.

not-ron said:

So are we saying there will be less drag with the extra plate in ? In the mean time I have stripped the clutch and found that one bronze plate and one steel plate were stuck together

Click to expand...

Yes, with the extra plate the spring will have less force and the clutch should disengage better. The thickness of the extra plate (and all the others) has a direct effect on clutch spring tension, and clutch pull. With no extra plate you get hard clutch and drag. With too thick a plate you get light pull and slip. It's a compromise.

I had a profound revalation when I replaced my bronze plates with a Barnett set. There was a noticeable reduction in clutch pull. Upon close inspection I found that the new plates were exactly .125" thick and my old broze plates had worn to .123" over the years. Five new plates made a .010" thicker stack and I could feel it. That lead me to experiment with adding extra steel plates of different thickness (thank you, Old Britts) until I found the sweet spot at .065". I now have a 3 finger clutch with no drag or slip. BTW the fiber Barnett's dragged terribly.

Most Commando owners will confess to doing a once-a-year clutch disassembly and cleaning. You'll see thread after thread here about what type of oil to use in the primary, how much, etc because the plates stick from being in oil. This is the first season in a long time that I haven't had to do that. ATF in the primary, Dyno Dave's clutch rod seal and magically spaced stackup works for me.

There's a graphic in the boot leg online NOC Service Notes.
Might see where the numbers posted here show up on it.

I've collected 3 pressure plates milled or bought in different
thickness and also a collection of steel plates.
I've played with various combo's and the best down and dirty
way for me was to get stack thickness so the diappharm
spring would just slip into its slot w/o hardly any slack
against the stack nor any pressure to feel it clear seat lip.

Plates are stamped out so have a rounded and sharp
edge, dragged finder can reveal which, install
so round edge allows easiest to expand apart,
spring takes care of over coming sharper edge.

I like the Barnett friction discs best, they should have
AFT applied then wiped off on first install company says,
or can wear in chatter pattern.

hobot

I can see the logic of the extra plate and will try that route, are the bronze plates 0.125 when new ? having measured the bronze plates from my clutch 4 are 0.119" and one is 0.120" this appears to be showing signs of wear and may account for the increased effort when using the clutch.

The extra plate has worked a dream a light clutch two fingers cable routing checked all good a very happy Commando owner.....Iv'e just voted on the T shirt page and entered my size and it has occurred to me that there are good many Commando's out there (mine included) whose perfomance would be greatly improved by the rider's reducing their calorific intake !! :lol: