Clutch impossibly heavy to operate - done everything - what's wrong ?

New springs?.  There are some duds out there, try the old ones. Only compress enough to kick it over without slippage.

... is the pivot to nipple centre distance on the lever? I'm not sure what yours should be (mine for a laydown box is 1 1/16") but if it's too big (as most aftermarket levers are) it will require a huge effort. Small distance = less effort required.

Having said that, you also report what sounds like dragging which suggests that there's not enough lift.

I assume the "AMC" type gearbox - have you checked that the operating lever in the box outer case is correctly located?

The model 50 isn't a torque monster, so it could be worth trying it with a plate removed (just one, not one of each). Obviously needs enough 'grip' to start it and ensure no slip when in top gear, but less plates = more lift for the ones stiĺl there. This did work for another member with a M50.

Regards, 

George 

Have you got the correct operating arm in the gearbox? The ones for diaphragm clutches have different profiles, but look nearly identical.

Is the arm at 90 degrees to the cable?

Got to agree with Robert on this puzzle. Your replacement, longer springs are probably too heavy and/or becoming coilbound.  Unlike cylinder head valve springs which get seriously cooked with each long ride the clutch springs tend to have a much easier life and do not shorten as much with use.

Put the old springs back and see if this sorts the issue.

Attachment gives some clutch spring lengths.

While you are re-fitting the old springs  have a look at the outside faces of the spring cups which can get ridges worn on them from contact with the center face plate. 

Because some bikes need them. The laydown and earlier boxes move the pushrod less for a given movement of the cable so need that extra travel (and the effort is commensurately less). My ES2 has 1.1/16 clutch and 7/8" front brake as the latter needs all the help it can get.......

As said, Grove sell 7/8" levers as does Steve Surbey at AMC spares.

The different lever pivot centers will make a considerable improvement to the pull effort ,but of course the reduction in lift also  means that everything else needs to be correct. With clutch springs I found that length is not the only thing that needs to be correct. Spring wire  gauge and temper are important too. As just about everything we buy is made (we hope!) to pattern there is always the possibility that some changes have crept in unnoticed. I am never in a rush to discard orriginal parts but there is also a need to keep the supply chain working. Hey ho. 

HI Mike Have you changed the clutch centre ( spider) it could be the early centers had lips on the ends of the splines and they get crushed over time and let the back of the centre bind on the sleeve gear ( sprocket carrier ). The later centres have a full washer fix in it for the spring washer and nut to hold the clutch on to the main shaft. I have found this fairly common.  

The attachments show what your bike should have and one of the later SS clutch variations.

Clutch pressure plates. Hi again. Doug here (Richard is my son).

I don’t have a pressure plate to compare to the pics. But what I do know is that because the Model 50 had two fewer plates than the ES2, the pressure plate for the M50 curls in more to take up the space.

Getting the clutch to lift and spin evenly  is a bit of  an art.  Not helped  by the drum which has enough slop on its bearing  to wobble and confuse the issue. I set up a dial gauge  which takes out the guesswork and ignores the wobbly drum. I set it up on the pressure plate and take readings at the point the clutch is starting to  drag. New plates will settle down and grip better and may need a couple of adjustments.