easier pull clutch adjustment

I recently came up with a neat trick, I'm sure someone has probably posted this before, but I feel like I should share it with anyone that will listen.
The Norton clutch has an adjustment on the cable at the hand lever, which attaches to a little lever in the gearbox, which pushes on a rod, and then finally there's an adjustment screw on the clutch basket/spring that hits the end of the rod. So there are two points of adjustment, the hand lever and the screw.
I pulled the primary apart, and putting it back together I thought I should follow what the book says: set the cable adjustment all the way in, and then adjust the basket screw.
I did this, and it seemed to work fine. Then I went for a quick ride around town, and by the end of it I thought my left arm was going to fall off. The clutch was way too hard to pull.
So then I went and adjusted the cable screw almost all the way OUT, leaving just a little, and then adjusted the basket screw.
What this does is change the angle of the lever inside the gearbox that hits the push rod.
The clutch is now way way easier to pull.

I would suggest that all you did was to position the clutch operating lever correctly...... They have a habit of dropping down if one rushes things and does not remember to ensure they are correctly positioned. Incorrectly positioned results in very heavy clutch lever action and drag problems in my experience ONCE in my youth riding from Eastbourne to Liverpool over night in thick fog most of the way up the old A5 ........the I.O.M. Srteam Packet Chiefy loaned me a drip tray and being the only bike on board (it was late September) I fixed the problem before reaching Douglas.... Happy days of youth and another Norton learning curve completed......

mkmachine said:

So then I went and adjusted the cable screw almost all the way OUT, leaving just a little, and then adjusted the basket screw.
What this does is change the angle of the lever inside the gearbox that hits the push rod.
The clutch is now way way easier to pull.

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Over-adjustment of the cable (and consequent under-adjustment of the pushrod to compensate) advances the operating lever to a point well into its range of movement to begin with, and therefore, it reaches the end of its useful lift travel before the handlebar lever is pulled in.
This does make the clutch action lighter but only because the operating mechanism has basically stopped lifting the clutch spring. I found this method of adjustment resulted in a marked reduction in clutch lift and although it seems to work for you, it isn't how I would want to set the lifter mechanism.

set the cable adjustment all the way in

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I fear you interpreted this wrongly by screwing it in "all the way" you went way past the point of just seating the screw on the tip of the rod inside and then backing off about 3/4 of a turn - is the correct way to set the flex point of the diaphram spring

and now I think you went the other way too far, backing it way off so not enough flex to lift the plates

someone needs to make a utube video of correct Commando clutch adjustment and post the link, it is SO easy to get it totally wrong

Some thoughts on the subject.
The clutch lift mechanism in the ANC gearbox was, I always understood, designed to be employed with a clutch lever having a distance between the centre of the pivot and cable nipple of 7/8 inch.
For good clutch drag free lift employing the moulded friction materials around in the 50s and 60s a clutch designer would design the lift mechanism to give approx 0.005 inch lift PER friction interface at full lift FOR A CLUTCH DESIGNED TO BE RUN DRY as Dommy and Commando clutches were designed to be employed. Thus with the old vibrator or Atlas as AMC called it and its 12 friction interfaces a lift of 0.060 inch was required for good dry drag free freeing off.
With the lift mechanism correctly set up and the ajuster freed off by approx 1/2 a turn the 7/8 inch clutch lever and the AMC clutch operating lever with the clutch lever back to the bar I measured the lift as approx 0.088 inch which was more than adequate for the Atlas clutch to free off wiothout drag occuring IF there was no oil on the friction interfaces that is.....
Now the Atlas Mk3 or Commando diaphragm spring clutch does NOT work like a coil spring clutch. Using the std AMC lift mechanism and 7/8 inch clutch lever you still get approx 0.088 inch at the release ring in the centre of the diaphragm spring but the outer edge of the spring is held in place and does not move and the point at which lift occures to the clutch plates (the raised lip on the pressure plate known as the pressure line) is approx half way between the edge of the release ring and the fixed in position outer edge of the spring so the lift IN THEORY at the pressure line / clutch plates is approx 0.044 inch. IN FACT because the 18 release ears / fingers bend I measured the lift as 0.037 inch which is inly just enough to allow drag free freeing off with the friction plates fully bedded in and with everything flat. i.E. it was not really enough lift.
The Commando was a 2 year bodge cobbled together using as many existing componants as possible to keep it cheap and requiring little spending of money or time and intended to keep cash flow flowing whilst new models were designed developed and tested...Hah Hah Hah!! They changed the clutch lever to one with 1 1/16 inch centres giving increased lift...... this gave approx 0.128 inch at the release ring and approx 0.055 inch at the friction interfaces...Problem solved....apart from the fact that more movement results in more work being done by the rider to deflect the diaphragm spring further......PLUS the AMC clutch operating lever fouled the inside of the gearbox outer case at getting on for full lift.....OOPS....they chomped a lump off the end of the clutch operating lever and gave it a new part number. Phew, problem solved .....well that one anyway!! It did not solve the problem of oil reaching the designed to be run dry frictiion interfaces within the clutch resulting in a VERY SERIOUS clutch slip problem that they NEVER managed to solve but going base over apex and closing down did!!
Now it has been suggested that to make clutch lever action lighter the clutch operating lever should be set in a different position although as its position is dependant upon the ball in the end of the main shaft locating it ...... Sorry but I simply cannot see this idea making much if any difference. Go do some simple testing and measure with a spring balance the difference it makes at the clutch lever and let us know the results and prove your idea makes a noticable difference.......and I would expect at full lift the clutch operating lever to be clouting the inside of the outer cover but I am NOT going to assemble a gearbox just to do the testing required to see what exactly is occuring because I would not have a heavy clutch lever problem to start with!!
There is a VERY SIMPLE WAY to make clutch lever action on later Commandos the same as it was on the early 750 models... Quote Early 750 road test....' I find it incredible that such a delightfully light and positive clutch could of been ignored by motor cycle manufacturers for so long before being introduced on the Commando'. The very first time I operated the clutch lever on one I turned to the owner and said 'OK so who is the clrver ******* who has disconnected the ******* clutch?!' to which the owner replied ' Funny but most people ask that question'. AND it did NOT suffer from slip during a two up fairly fast lap of the TT course but my money is on the clutch still having dry friction interfaces.....Change the diaphragm spring to the early 750 0.075 inch think version (if you can find one that is!)which gave a clutch lever EASILY operated by two fingers all day long....... Of course assuming you know how to correctly set up the diaphragm spring you will of reduced the clamp load being given by the diaphragm spring from the approx 550 lbf of the later 750 and 820 clutch 0.084 inch thick spring down to the approx 380 lbf of the original spring and also the amount of torque the clutch will transmit by the same percentage but if the clutch is being run DRY it should not slip even fitted to 820 lumps, even with those rediculously heavy bronze plates fitted...its oil that causes the slip. As the staff of The Motor Cycle stated decades ago in their book ' Speed and How to Obtain it' the idea of shoving a clutch within an oil bath chain case was and I quote 'FRANKLY A COMPROMISE' and that a much better idea was to employ the chain within the oil bath CHAIN case along with lots of nice chain cooling oil but the clutch externally so it could be employed DRY!! If course if you convert your chain case to a belt case and run your AT10 etc belt dry as they were designed to be employed ....... Some clever souls run AT10 belts on Nortons with oil!!!!
Another idea that works rather well giving very light clutch lever operation on a friends 650SS which would i suspect also work on an Atlas is to modify the inner and outer covers to incorporate the older more expensive to produce worm lift system... If course he does know how to CORRECTLY fill his chain case and the correct oil to employ plus he uses a Renold singlex chain that was, I understand, of rather high quality made for Harrier aircraft...... AND he cleans his clutch every 10,000 miles or so to remove any oil working into it.
Personally when I cobble togeter a DRY belt drive diaphragm spring clutch system (FOR FRIENDS ONLY) 920 etc Commandos / Triumph and BSA twins / B50s etc the clutch levers are easily operated by the rider ..... as Mr Irving laid down many decades ago as one of the qualities a motor cycle clutch should possess..... no more than two finger operation just like the early 750 Commando clutch lever.......
I do laugh when I try some owners clutch levers.......
As I said at the beginning..only a few thoughts.....

J. M. Leadbeater said:

It did not solve the problem of oil reaching the designed to be run dry frictiion interfaces within the clutch resulting in a VERY SERIOUS clutch slip problem that they NEVER managed to solve

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My 850 Mk3's standard bronze plate clutch is not heavy and neither does it slip even with the primary case filled with more than the recommended "200cc" of oil (20w-50) :roll: and I think we are getting pretty tired of repeatedly hearing how our clutches are all supposed to slip when in fact they don't.

J. M. Leadbeater said:

I would expect at full lift the clutch operating lever to be clouting the inside of the outer cover but I am NOT going to assemble a gearbox just to do the testing required to see what exactly is occuring because I would not have a heavy clutch lever problem to start with!!

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If cable and arm are considerably over-adjusted, then the lift arm will (obviously) come to a dead stop inside the case, however, by that time, the arm is beyond "full lift" as I stated previously.

A Venhill "Featherlight" clutch cable will lighten up the lever pull by about 25%. Needs no oil as well.

Slick

texasSlick said:

A Venhill "Featherlight" clutch cable will lighten up the lever pull by about 25%. Needs no oil as well.

Slick

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Totally. 'Love mine!