Clutch Finger in Gearbox Out of Place

When I built this 1972 750 Commando in the mid nineties, I upgraded the clutch to the 850 plates from Barnett. I had read about improving the clutch in Norton Notes or elsewhere. Somehow, I missed the part about needing a new thinner 850 pressure plate to replace the thicker 750 unit. Natch, things wouldn't fit so I left out one friction plate and one driven plate and reassembled to see how it would work out. If it slipped, I could always look into it later. All the bits were meticulously aligned and the cable was well lubed.

As it happened, the clutch did not slip and neutral was easy to find. The clutch lever was VERY tough to use and I never tried any motorbike clutch that was anywhere near as tough. For whatever reason, I did not associate my odd clutch stack with the tough to use lever. As the bike neared completion, I used one of those grip exercisers to strengthen my hand and found that after a days riding my hand was so tired I started to avoid any unneeded gear changes. Everyone who tried my clutch lever said that there was something wrong.

The bike sat for twelve years due to rear hub problems detailed on a previous thread and now that the Norton is the current project again, other niggles are being addressed, the heavy clutch among them. Phil Radford at Fair Spares had hipped me to the pressure plate issue and mentioned also that the clutch finger might be out of place so the first pic below was shot to verify if the finger was where it should be. The primary cover was taken off and the new 850 clutch stack Phil had shipped was installed with a used 850 pressure plate. Everything fit right in this time!

The pushrod was reinstalled but the finger in the gearbox seems to have slipped out of place and has so far resisted all attempts to raise it back into position. Is there a trick to this? I remember having this issue with my first Norton forty years ago after replacing the kickstarter pawl but can't recall how I licked the problem. Any tricks to it? See the second pic.

Clutch finger before I messed with it:


Clutch finger after I messed with it:


Vintage Paul, close to having a useable clutch!

hudson29 said:

the finger in the gearbox seems to have slipped out of place and has so far resisted all attempts to raise it back into position. Is there a trick to this?

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The clutch pushrod adjuster must be slackened right off first.

I have it completely off and the pushrod is pulled well back. Shouldn't that finger be easy to just pull back up?

Vintage Paul

As L.A.B. says, you first have to loosen the adjuster nut a bit to let you get the actuating mechanism back in place. The more clearance you have in your clutch pack the harder the clutch will feel, as the diaphragm spring has to be pushed further to get it over centre and thus release the pressure. Try putting back one or more of the plates that you omitted and you will most likely feel a massive difference with the clutch action, now that you have actually run the bike you might get all of the plates in. I believe the Barnett plates are slightly thinner than the original plates.

dave M said:

As L.A.B. says, you first have to loosen the adjuster nut a bit to let you get the actuating mechanism back in place. The more clearance you have in your clutch pack the harder the clutch will feel, as the diaphragm spring has to be pushed further to get it over centre and thus release the pressure. Try putting back one or more of the plates that you omitted and you will most likely feel a massive difference with the clutch action, now that you have actually run the bike you might get all of the plates in. I believe the Barnett plates are slightly thinner than the original plates.

Click to expand...

Phil Radford sent a complete new set of 850 friction plates by Barnett and an additional driven plate to bring the total right up to snuff. It all fits fine right now, the only issue is that pesky finger that has dropped out of place. I tried prying it up with a screwdriver but it refused to come all the way back up. Maybe some sort of tool with a hooked end might help?

Vintage Paul

hudson29 said:

I have it completely off and the pushrod is pulled well back. Shouldn't that finger be easy to just pull back up?

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The upper lobe of the arm has to be persuaded to go back over the ball. As it can easily drop out of position, then it shouldn't be too difficult to get it to go back again if it's levered/pulled in the right direction. I know I've done it myself before, but I couldn't describe exactly how I did it.

Hi, as long as the pushrod is free as said before , just put your finger (only one!) through the inspection hole, underneath the clutch finger and push it towards the top, maybe you have to play a bit , when it is up , maintain it while screwing inwards the clutch adjuster screw and thus pushing the rod which will then press again that PITA lever.....it takes longer to explain than to do............!

You might have to loosen the adjuster stud on the clutch, then what I do if there is no one else around to hold the arm out in position, I grab it with a pair of hemostats to hold it out and then tighten up the adjuster, making sure the arm stays like your first pic. You will have to go through all the adjustments after this.

Dave
69S

It's possible that the ball may be a tight fit in the finger carrier, this can also lead to a stiff clutch. Now that you have loosened the push rod, try tapping the finger inwards with a soft drift to see if it moves the ball in a bit. The ball should slide easily in and out with almost no perceptible resistance.

Ok, guys, thanks for the tips. I'll have another go and see what happens. Often another try with a fresh brain in the morning clears these matters up.

Vintage Paul

A Commando clutch should be one finger, maybe two.

If not, either get better fingers or fix the clutch. :mrgreen:

Just as some of you said here, the lever did go back into position after a bit of fooling with it. The clutch is still very heavy compared to the J-bikes I have been riding recently but it does seem better than it was with the partial 850 pack in it. Are the teflon lined cables a big help in lowering the pull on the handle? If so, one of those may be worth the extra expense.

Vintage Paul, better clutch in hand

hudson29 said:

Just as some of you said here, the lever did go back into position after a bit of fooling with it. The clutch is still very heavy compared to the J-bikes I have been riding recently but it does seem better than it was with the partial 850 pack in it. Are the teflon lined cables a big help in lowering the pull on the handle? If so, one of those may be worth the extra expense.

Vintage Paul, better clutch in hand

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The right stack height is the first thing you go for.

http://www.oldbritts.com/ob_clutch_info.html

Figure out how far off you are from optimal height. Rectify. Then try it at the handle.

There should be no problem pulling the commando clutch unless something is amiss. Is there a lot of slop between your clutch pack and the large circlip holding it all in? Like I've said before, about 3/4 way to the handle, the clutch should feel like a compound bow and break over and be very easy to hold.

Dave
69S

just my 2 cents. I have found that it is really easy to adjust when you have 2 people, one on one side holding the arm in position while you tighten the adjuster at the hub. don't know why that arm falls down the way it does, as I'm not a full time Norton nut. seems like a sloppy design to me, but what do I know

The Old Brits page was very helpful. With the five Barnett friction plates and four driven plates, we are still well under the lip of the splined basket. It COULD take a thicker plate or a shim of unknown size. I just buttoned all of this back up with a new seal on the chaincase so I'll have to give this whole thing some more thought. I have been working on this bike off & on for 20 years so there is no real hurry to finish it beyond just wanting to see it completed and actually ride it again. This thing is almost a project of the mind more than just a machine, I do think about it a lot . . .

Vintage Paul

I had a stiff pull also. What I did was get a new cable and lube it well as well as the hand lever pivot and cable ends and it was real smooth to operate. Perfect alignment of the clutch lever in the gear box is critical.
Once all that is done you should be good.
Start with a new, well lubed cable and route it so there is as little bends in it.

hudson29 said:

The Old Brits page was very helpful. With the five Barnett friction plates and four driven plates, we are still well under the lip of the splined basket. It COULD take a thicker plate or a shim of unknown size. I just buttoned all of this back up with a new seal on the chaincase so I'll have to give this whole thing some more thought. I have been working on this bike off & on for 20 years so there is no real hurry to finish it beyond just wanting to see it completed and actually ride it again. This thing is almost a project of the mind more than just a machine, I do think about it a lot . . .

Vintage Paul

Click to expand...

Did you note in the OldBritts article that they sell additional metal spacer plates of varying thicknesses to add to the clutch stack to bring it up to just below the circlip groove. You can get several thicknesses and then return the ones that you don't need.
I used one plus a Teflon lined Venhill cable and my clutch is a two finger pull instead of the gorilla's handshake it was when I bought the bike.
Still the original friction plates that probably had lost thickness with wear and now a smooth no slip clutch.

Bob

If the clutch pull is still heavy with the correct stack height and Teflon-lined cable you might consider the Atlas operating lever--I believe DynoDave had a thread on the various merits of different rotating radii on the clutch actuation cycle


Tim Kraakevik
kraakevik@voyager.net
'72 Combat, '74 RH10 850