Clutch nuts

[UKlittleguns]

Hi Everybody,

Nearly finished my rebuild.  The clutch is far too heavy.  It is a 4 spring and all brand new.  The slotted head spring compression screws were set level with the bolt ends.  They screwed in easily.  Backing them off if proving a right (rude words!).

The nuts have a dimple underneath their heads.  This clicks on the end of the spring.  Excellent for locking them but they will not unscrew to give any adjustment.  Any attempt simply fights the spring.

Anybody experienced this or have a solution?

Best Regards

Len

[muskrat]

G'day Len.
Yes they can be a PITA. Don't push too hard on the nut, the square head of the bolt comes off it's seat and spins. So it' turn with little push.
Cheers

[JulianS]

To undo the nut slide a blade between spring and dimple.

I find that handlebar lever with 7/8 centres give a lighter more progressive clutch than the lever with 1 1/16 inch centres. The later gives more lift but at the expense of a more sudden and heavier action.

Make sure the cable is well lubricated and has a smooth curve.

[berger]

set my 4 spring up today and got it true showing about 1/1/2 coils of spring proud of the cups and it feels good, trying it out tomorrow without oil in the case so I can adjust it if needed without having to drain the oil.

[morris]

As JulianS, a small flat screwdriver blade between nut and spring. Lift the spring backward while turning the nut. Has to be repeated every turn so needs a little patience

[beezermacc]

If you compare the pattern nuts with the originals you will see that the pattern ones have a dimple which is much bigger than the originals and much bigger than necessary. You can take some of the sharp edge off the springs with a Dremel or similar so that they skid over the dimple when unscrewing them. In fact if you don't do this you'll need to use a blade as previously mentioned or you'll mangle the springs. Obviously you don't want the nuts to unscrew themselves when in use so be careful!

[chaterlea25]

Hi
Some suppliers put the wrong springs in a 4 spring kit
They include the ones intended for 3 spring A65 clutches
Search the forum for previous discussion

John

[Jules]

Ref. Julians comments about 7/8 vs 1 1/16 levers, I thought that the bigger the distance the better the leverage hence lighter clutch, which was the "preferred" selection for the 6 spring clutch??  A picture of each would be helpful if anybody has them and maybe an explanation of maybe why each is better for a given clutch??
I'd rather spend the time now setting up my (6 spring) clutch function for easy(ier) lift/short(er) throw first, then use the lever that best suits the function to finish off (as per my questions about different cables), I'm in no hurry... 
I'm keen to get my 6 spring as light and manageable as possible as part of the build, rather than after the event if I can...thanks

[orabanda]

I just sorted out the clutch on a G15 matchless.
It was so heavy it was difficult to use.
I replaced the 1 1/8" centres lever with a 7/8" lever and the clutch is now light & easy to use. The travel is reduced, so the engagement is different (more abrupt), but a good outcome.

Richard

[Jules]

thanks Oranbanda, what cable/supplier are you using? cheers

[orabanda]

Hi Jules,
I buy cable kits and components (inner cables, outers, ferrules etc) from Venhills, then make to suit.

I have also invested in Venhills excellent cable making tools (cable cutting pliers, birdnesting jig); well worth the money.

Richard

[groily]

I just sorted out the clutch on a G15 matchless.
It was so heavy it was difficult to use.
I replaced the 1 1/8" centres lever with a 7/8" lever and the clutch is now light & easy to use. The travel is reduced, so the engagement is different (more abrupt), but a good outcome.

Richard

Spot on Richard.
On my 4 AMCs, 3 with AMC clutches and 1 with Burman, 7/8 centres are critical for smooth and light operation and a very common discussion point in that parallel universe. The difference can be extraordinary, certainly on the (three spring) AMCs. The diaphragm version that came later was a long overdue improvement - but still not really 'light' compared to some others.
On my A, larger centres on the lever do actually seem fine though, as the 4 spring clutch with Surflex plates is an easy two-finger job, almost as light as the old 5 spring Burman.
Cable and cable routing with gentle sweeps being the other key ingredients for 'happy'.

[orabanda]

thanks Groily.
As you pointed out, attention to the cable (nylon inner, routing) also reduced the clutch heaviness, but the closer fulcrum point was the biggest improvement.
Followed by adjusting the springs with a dial gauge on the outside of the aluminium outer plate. AMC books say to adjust the clutch so that each nut screws onto the stud until the top of the stud is level with the top of the nut.

All three springs were the same pressure  (measured 130 Lb). When finally set up (pressure plate run out of 0.003"), one nut was was level with a stud, one was 3/4 turn proud, and the third one was 1 1/4 turn proud. Owner complained the clutch used to drag and he couldn't find neutral when the engine was running. After truing the pressure plate, neutral was easy to find. Moral of the story; worth truing the outer plate.

When I fit Suzuki clutches to the swing arm "A'"s, the 1 1/8" is the better lever to use, as the 6 plate Suzuki's seem to need more lift (travel), and they are a light clutch anyway.

Richard

[RDfella]

I only treat instructions of where clutch nuts should be as a guide. Like many, I want a clutch that is smooth, does not slip and is light. To this end I only adjust nuts far enough in to avoid slip, and then set about ensuring the plates separate evenly ie outer plate lifts square. On some bikes one also has to ensure the nuts are not so far out that they hit the outer primary case. If this happens, I’d rather shorten the springs 1/8th than have a heavier than needed clutch. Of course, as others have said, cable bends must be kept as big a radius as possible. Also, important that the cable is robust enough – too light a cable and there’ll be compression of the outer on operation, reducing clutch separation. As for levers, you take your choice. large hinge to cable distance means heavier clutch but greater plate separation. Smaller hinge/cable dimension = lighter clutch but risk of dragging. Diaphragm clutches are the answer but, having said that, the racing clutch on my Weslake is a nightmare. Really heavy. I've tried re-profiling the actuating cam (AMC box) for some improvement, but still not great.

[Greybeard]

OK, I have my tin hat on; shoot me if I'm wrong. This sketch is my understanding of changing the fulcrum-to-cable distance on a clutch cable. What am I missing?

The explanation is on the next page!