Lost Clutch.

lwmcd1 · Nov 9, 2015

Morning All,
I've dealt with this problems several times now with no good results.
Here are my symptoms, I take off and it's fine I get to second gear OK but when I attempt 3rd I lost all clutch and all tension on the cable. I pushed it the couple of blocks back to the house and back on the rack and magically I had clutch again. I'm thinking the clutch plates are sticking but I just cleaned them the first time around with this problem. The center clutch hub is not notched. I've got it all apart, Again. I saw that the center hub nut had turned slightly but not to the extent that the basket was loose. This was indicated by the flat of the tab washer no long tight against a flat on the nut, it was against a point on the nut. I have new Sureflex plates on the way. Which I will use when I get this figured out or somebody helps me figure it out for me.

Cheers,
Larry
P.S.
I just realized that sticking plates will only tighten the cable not loosen it so that can't be it.

gripper · Nov 9, 2015

Check the cam in the inspection cover on the right hand side of the gearbox. ( the bit the cable end sits in) If it is soft it has probably worn and thrown up a burr, binding in it's fork, holding the clutch apart. get a later cam which should have a better profile and be hard/harder.

lwmcd1 · Nov 9, 2015

I did as you suggested the lever seemed fine but I did notice that the it was not "exactly" lined up with the hole the cable fits through. I corrected that. When my new plates come in I'll see if that has any bearing on my problem.

o0norton0o · Nov 9, 2015

Your clutch basket is fixed in place with a circlip which is behind the basket. Your clutch springs push the plates against the basket to make your plates grab each other. IF,..... your clutch basket circlip jumps out of the groove, then your clutch springs just push the basket down the shaft and don't compress your plates....

IF this is happening, then the tell tale sign of this is if your clutch basket had ground away at your inner primary case behind the basket.

If this is your issue, hopefully the shaft or the clutch basket isn't the problem and the recess in the shaft is undamaged. If it's just the circlip that is worn out, it's an easy fix.

The circlip is behind your clutch basket on the shaft, and when the clutchbasket is mounted it captures the circlip so the circlip can't expand and jump out of it's groove on the shaft. This is how your clutchbasket resists the force of your clutch.

Just pushing the bike back to the garage may allow the final drive chain to spin the shaft enough for the basket to move forward enough for the damaged circlip to pop back into it's groove...

*I've had this issue and a new circlip fixed it entirely...

Torontonian · Nov 9, 2015

Larry check that ramp.. Also the bend-over tab washer for main shaft clutch retentions is a P.O.S. that will sooner or later create backoffs etc. Also the mainshaft circlip behind the clutch can be a p.o.s. too if the nut is overtightened ( crushes circlip creating more progressive slop ) like what the manual says , so ignore that nonsense and tighten less , using loctite. Get a better washer. The circlip can be replaced with a thicker version , used with the 75 e-start model starter system. It's a tad too thick , so spin it circular on emery cloth , clean then test to see if it taps tightly into the mainshaft slot. That's the goal . Rock n' roll.

bill · Nov 10, 2015

if you want more help on this i am just south of you in apopka.

batrider · Nov 10, 2015

I'm sure bill will be able to straighten this out. Another thing to check is the nut on the right side of the mainshaft. If this loosens then the clutch basket will move out and you will lose clutch action. Walking the bike eventually moves the clutch basket and mainshaft back into place. This nut is under the clutch cam mechanism. You may want to get the special tool to undo the lockring rather than the punch method. This happened to me in 1972 in the Poconos in the middle of nowhere. The bike had about 1000 miles on it.

lwmcd1 · Nov 15, 2015

bill said:
if you want more help on this i am just south of you in apopka.

I’m posting more about my slipping clutch.
The clutch slips so bad as to be unable to turn the motor over with the kick start.
I’ve cleaned the plates.
Got the stack height very close.
The depth in the basket to the groove measured 1.243.
The stack height of the plates with pressure plate measured 1.246.
It should have been to large to fix in the large circlip but with difficulty I got it in.
I used a new small circlip.
I tried different friction plates (Sintered Bronze).
All to no avail.
If you have any suggestions I would love to hear them.
Cheers,
Larry (lwmcd1)

Torontonian · Nov 15, 2015

Tough one. Your diaphram spring plate is weak a remote possibility. I would back off the clutch pushrod adj. nut enough that the pushrod does not rest on it a-la manual and try to kick it over again. If it slips again kicking the start all over , by removing a plate and entertaining other ideas. :shock:

lwmcd1 · Nov 15, 2015

Torontonian said:
Tough one. Your diaphram spring plate is weak a remote possibility. I would back off the clutch pushrod adj. nut enough that the pushrod does not rest on it a-la manual and try to kick it over again. If it slips again kicking the start all over , by removing a plate and entertaining other ideas. :shock:

Thanks, I did that already and I switched out the Dia. spring.

kerinorton · Nov 15, 2015

o0norton0o said:
Your clutch basket is fixed in place with a circlip which is behind the basket. Your clutch springs push the plates against the basket to make your plates grab each other. IF,..... your clutch basket circlip jumps out of the groove, then your clutch springs just push the basket down the shaft and don't compress your plates....

NOT CORRECT The clutch spring only exerts force on the clutch assembly internally within the assembly.

The circlip is behind your clutch basket on the shaft, and when the clutchbasket is mounted it captures the circlip so the circlip can't expand and jump out of it's groove on the shaft. This is how your clutchbasket resists the force of your clutch.

ALSO NOT CORRECT. The nut holding the clutch to the shaft, carries the force exerted by the clutch throw out mechanism [ your hand, levers and cable etc ].. So do the bearings on the main shaft, and naturally, the main shaft nut inside the gear box carries that force as well.

I have experienced both main-shaft nuts coming loose. The internal one is not a pretty sight if that happens, nor are all the metal filings inside the g/box.

I suggest your problem is within the clutch , unless the pushrod is jamming the clutch in the disengaged position. Let someone experienced in this matter help you diagnose the real problem. Let us know what you find.
Dereck

lwmcd1 · Nov 15, 2015

" someone experienced in this matter"
That's just what I'm hoping for. That's why I came here, No better place that I can think of.

kerinorton · Nov 15, 2015

Hi Larry. From your descriptions, all should be ok. By having someone experienced have a look at your problem you may find the answer. Not always easy to diagnose over the internet.,
Dereck

Keith1069 · Nov 16, 2015

The depth in the basket to the groove measured 1.243.
The stack height of the plates with pressure plate measured 1.246.
It should have been to large to fix in the large circlip but with difficulty I got it in.

Does that not indicate something? Is there a chance the diaprahgm is already on the point of release once the spring compressor is released? What plates and how many? I use 4 steels and 4 Surflex or RGM Ferodos currently. My dimensions with 4 steel, 4 Surflex = 28,5/1.112", Pressure plate = 5,92/.233". I don't have the basket dimensions and it is aluminum but clutch has similar feel to the steel one it replaced with same plate combo. Is the adjuster backed off at least 1/4 turn? Does the pushrod move freely thru the mainshaft using the lever with the adjuster removed? If yr cable has lots of play in after operating it then the pushrod or some part of the mech is still in its operated position, not the other way round. Is the operating lever sitting in place on the roller? Usually it drops down in the housing and the clutch will not operate but worth a check.

L.A.B. · Nov 16, 2015

lwmcd1 said:
The stack height of the plates with pressure plate measured 1.246.
It should have been to large to fix in the large circlip but with difficulty I got it in.

According to the dynodave data, normal stack height should be 1.167" (4 friction plate + "thick" pressure plate) or 1.172" (5 friction + "thin" pressure plate).

http://atlanticgreen.com/clutchpak.htm

o0norton0o · Nov 16, 2015

kerinorton said:
o0norton0o said:

Your clutch basket is fixed in place with a circlip which is behind the basket. Your clutch springs push the plates against the basket to make your plates grab each other. IF,..... your clutch basket circlip jumps out of the groove, then your clutch springs just push the basket down the shaft and don't compress your plates....

Click to expand...

NOT CORRECT The clutch spring only exerts force on the clutch assembly internally within the assembly.

Yes, I was incorrect... I wish I could edit my previous post... I would rather wrong information be eliminated here...

kerinorton said:
The circlip is behind your clutch basket on the shaft, and when the clutchbasket is mounted it captures the circlip so the circlip can't expand and jump out of it's groove on the shaft. This is how your clutchbasket resists the force of your clutch.

You seem to be agreeing with my mistaken earlier post in this last sentence. As you said initially, the force of the clutch only operates within the basket, so the circlip on the shaft does not resist the force of the clutch... << this was my incorrect original statement that you pointed out was incorrect... thanks btw...

** And the classic problem of a clutch that works fine and then seems to have no tension is usually a notching of the basket splines that prevent to pressure plate from compressing the clutch plates... but I think the OP said there was no sign of that...

concours · Nov 16, 2015

The transmission mainshaft/pushrod/actuator is suspect here. That RH bearing, being retained by the nut/pivot assembly must be examined. Have you checked that the items 33-39 shown here are all present and aligned as they should be? http://www.oldbritts.com/1973_g9.html

concours · Nov 16, 2015

lwmcd1 said:
bill said:

if you want more help on this i am just south of you in apopka.

Click to expand...

I’m posting more about my slipping clutch.
The clutch slips so bad as to be unable to turn the motor over with the kick start.
I’ve cleaned the plates.
Got the stack height very close.
The depth in the basket to the groove measured 1.243.
The stack height of the plates with pressure plate measured 1.246.
It should have been to large to fix in the large circlip but with difficulty I got it in.
I used a new small circlip.
I tried different friction plates (Sintered Bronze).
All to no avail.
If you have any suggestions I would love to hear them.
Cheers,
Larry (lwmcd1)

How about the diaphragm spring popping over center/installed incorrectly/failed....... :idea: item 46 http://www.oldbritts.com/1973_g10.html
Have any of you 45 year Commando vets seen this done before? 8)

OP, we'll need some pics please :mrgreen:

bill · Nov 16, 2015

as I stated earler I am about an hour away when you get tired of screwing with it. check your PM's

lwmcd1 said:
" someone experienced in this matter"
That's just what I'm hoping for. That's why I came here, No better place that I can think of.

N0rt0nelectr@ · Nov 16, 2015

The roller for the clutch lifting mechanism can develop a flat spot which will affect the clutch action. Whether this is the cause of you problems but it is worth looking at.
John Ebert
Texas

Lost Clutch.

lwmcd1

gripper

lwmcd1

o0norton0o

Torontonian

bill

batrider

lwmcd1

Torontonian

lwmcd1

kerinorton

lwmcd1

kerinorton

Keith1069

L.A.B.

Moderator

o0norton0o

concours

concours

bill

N0rt0nelectr@

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