Clutch Problem

[trevinoz]

Once you get moving you should be able to change gears without using the clutch, so I agree with TT. Hope I am proved wrong!

Trev.

[BSA_54A10]

how long is your clutch push rod ?

[duTch]

how long is your clutch push rod ?

 Geez Trev- getting a bit personal...??

 

[bikerbob]

Just checked the length of the push rod and I believe it is the correct length 11.5" I have readjusted the clutch at the gearbox end and the clutch control arm is parallel with the gearbox when you pull the lever in and there is a small amount of play at the clutch control arm and the lever. Now on start up when you engage first gear the clutch is still dragging quite a bit you can feel the bike trying to move forwards you can with difficulty get it into second  and other gears if you press the kill button whilst in gear you can feel the bike relax.  So the problem to be sorted is to get the clutch working correctly everything is adjusted correctly according to the books.  2 things come to mind,  I have not replaced the clutch springs but have ordered a new set also When I dismantled the primary to cure the oil leak which now looks solved some previous owner had only replaced 3 of the 5 friction plates the other 2 were very badly worn to such an extent that the friction material was  starting to break away. Did this owner try replacing the other 2 plates as well and ended up with the problem that I am now having with a dragging clutch and to cure it refitted the 2 worn ones to stop the dragging clutch. Your thoughts would be helpful in trying to cure this problem could it be down to worn springs as these are the only items that I have not renewed yet but they did look OK I would think that worn springs would give you the reverse effect a slipping clutch

[muskrat]

The most common fault to cause a dragging clutch is the pressure plate not lifting squarely or badly worn/notched chainwheel/hub grooves.
Cheers

[a101960]

The most common fault to cause a dragging clutch is the pressure plate not lifting squarely or badly worn/notched chainwheel/hub grooves.

I agree with muskrat. If the chain wheel grooves are OK then setting the clutch lift with a dial gauge is the way to go. I bought a dial gauge and set my clutch up with it. Visually it looked to be lifting squarely, but the gauge showed that this was far from the case. It required a bit of time and patience, but it was well worth the effort. My clutch is now light in operation and drag free, what is more I can easily select neutral from either first or second gear while stationary. I could never do that before. The gearbox operation has been transformed too. Before setting up the clutch the box could be quite notchy in operation. So much so that I thought that I had gearbox problems.

[duTch]

 Is worth also considering the condition of the end of the push rod, and its contact surface on the pressure plate.
 I reckon even when these are in good nick, the fact that the pushrod has a bit of slop in the mainshaft makes any 'finely tuned' pressure plate run-out fairly arbitrary, if the contact is not dead centre...

 I'm also thinking;-
 Is it possible you've overtightened the springs...?   Sorry, I'm forgetting whose problem this is.?
 If the springs have lost their set (or tension), wouldn't it be more inclined to slip? -(unless they are so screwed up they become bound)
I ordered new springs and expected left hand winded like I believe the originals are, but the new ones are R/h- theory being the L/H ones catch on the lumps on the nuts to prohibit undoing...any thoughts on this..?

[trevinoz]

Have a measure of the fulcrum on your handlebar lever. If it is 7/8" you will have a dragging clutch forever, Bob.

Trev.

[chaterlea25]

Hi,
There are different depth spring cups depending on how many clutch plates are fitted,
Quite common now to find incorrect parts fitted 
It sounds from your description that the springs are coilbound when the clutch is pulled in? so no room for the plates to free, maybe thats why the previous owner had a lesser number of plates fitted??

HTH
John

[duTch]

 'Coilbound' term as per what John said is what I meant, but couldn't get my finger on..

 Actually, I've been experimenting with five (5) friction plates on a plunger 6spring....!
.....so the nuts don't screw on as much as I'd like, however, same principle......(more on this later)

What I do for now is hold the hand lever in with a hose clamp, and get the adjustment ok, and as per previous sentence, just short of coilbound, and back it off a beesdickor two (depending on the Bee)..works ok



 

[bikerbob]

New springs arrived and when checked against the originals  they are about 5mm shorter. Fitted the new springs and adjusted the clutch and there is a big difference, lever is easier to operate and when pulled in the clutch is much more free when you press the kickstart so I put everything back together and went for a short run. Can select all gears but with difficulty goes into first OK but when changing to second you have to press really hard on the gear lever same for all the other gears both changing up and down. I set up the pressure plate using a dial gauge and have checked the fulcrum length and it is about inch and eighth centers. The gears go in perfectly without the engine running but are difficult with engine running so am inclined to think the gearbox is OK or maybe I should try and adjust the cam plate plunger mechanism under the gearbox or do you think the clutch is still the problem I cannot select neutral with the engine running you get either first or second. I still think I am getting a bit of clutch drag although since changing the springs it is a lot better I could back off the adjuster screws a bit but I would not get a full locknut on.

[duTch]

 If it selects gears ok not running, I don't think the camplate plunger is the problem....?
 Just measured my fulcrum at 1-1/16" which I think is what others have, so yours should be pulling heps maybe too much?
 For the sake of curiousity, how long are your springs, and did you note how many coils in the springs- new and old..?
 Without reading all posts, has gearoil been mentioned? Maybe it's too thick- or none ?
 Hope you sort it soon, 'cos any undue force on the changes will wear the camplate/sel.forks/dogs
 

[BSA_54A10]

The six spring clutch was used on the entire range in one form or another so there are about 4 different cup depths and about 8 different spring lengths.
Things like M20's used tha same basket but fewer plates as did the B31-33 but the B32 & 34 used more plates as did the A 7-10. All of these parts can be mixed up and oft are even on the same bike.
Next the clutch adjusting procedure shown in the manual is way way too stiff.
You can just about tow a steam loco with the "text book" set up.
Usually I get the plate to lift square then back off each nut identical turns till the clutch just slips when you kick the engine over in gear with the front wheel firmly up against a wall. From there I tighten around 1/2 turn each and go for a test run without primary cover ( messy) for final adjustments.
1 to 2 flats (1/6 to 1/3 turn ) tighter than just starting to slip is generally fine.
Take notes so if you find it slips a bit then go 1 flat tighter.
The lighter the clutch the less wear in all parts and the less tendency for the pressure plate to flex .

Finally we get to the pressure plates themselves.
They were stamped out of sheet which had a definite grain. These blanks were then tossed into stillages, pressed again then tossed into stillagges and finished off thus the orientation of the grain to the holes is quite random. If your pressure plate ended up with the grain running directly through one cup hole on through the center nut then to another cup hole ( a symetrical axis ) then the plate will flex no matter what you do and this is the same for 6, 4 or 3 spring clutches.

[bikerbob]

I have  again dismantled the clutch and carefully checked everything and can find nothing wrong. So I put it back together again and refitted the adjuster nuts and tightened them up finger tight tried the kickstart and the clutch was slipping so I tightened them up a bit further keep checking the kickstart now I have it so that it is not slipping or dragging, the clutch is light to operate I would like to leave it at that but I cannot get a full lock nut on only about half a nut if I tighten the adjusters till can get a full locknut on you can feel the clutch plates are not entirely free. I have trued the pressure plate up using a dial gauge and it is within a couple of thou.  I have a small lathe so over the weekend I will take the adjuster nuts and machine small amount off each nut and then I will probably be able to get a full locknut on  and try the gearchange again and if still a stiff gearchange I will have to have a look at the gearbox fortunately I do have a spare gearbox that has been sitting around in the garage for about 20 years. Thanks to all those who have come up with possible solutions.

[wilko]

 Just ditch the locknut and use loktite. I do anyway.