Early clutch issue

I hope that your clutch plates are the early type with friction plates tags out and plain steel ones tags in.

Have you made certain that the clutch lever arm on the quick thread is tight enough? If the arm slips, you will lose the clutch lift. It does need to be tight. Use a ring spanner which has minimal offset, and is as near flat as possible

When I set mine up on my horizontal box, I make sure the cable is happy, that the lifter arm is as far downward as possible, put a screwdriver in the slot in the end of the quick thread and twist clockwise, and with my third hand, tighten the nut on the lifter arm. Don't forget to do it up good and tight......

Actually, on a Doll's Head box the job is much easier because the clutch lifter mechanism is exposed

The Norton clutch is a strong unit, able to cope with 50 bhp from the Atlas, and with fewer plates, the Manx....

Paul

I had problems with the lever turning on its shaft. Solved by removing it and running a hacksaw through the slot. It was not gripping. No problem since.

Would also be worth checking the clutch centre nut in case that is coming loose and allowing the clutch assembly to drift outwards.

Ian McD

Oh no - not the clutch centre nut again!!

George

How is the thrust washer in the gear box? Is it worn?

G

Nicholas - I know you say the clutch retaining nut is tight but Ian has a point (as I know to my cost). It is easy enough to check the clutch retaining nut. The symptoms you describe have all the elements of a loose nut. At least it will remove it for the suspects list.

G

Your reply makes it sound as though the quick thread needs to be re-adjusted, to eliminate lost movement.

Have you tried loosening the clutch lifter arm on the quick thread, use a screw-driver to drive it in as far as it can go so that there is no free play, and then re-set the lifter arm in a low position and tighten the lifter arm nut.

Paul

Previously nicholas_reeves wrote:

Thanks for your reply Paul. Yes the plates are correct and the clutch arm is tight. The problem seems that when you lift the clutch arm by hand ie cable not attached , it can be lifted to the top of its movement but with no resistance at all. In other words it seems that the worm is moving in to push on the push rod but doesn't reach it. If that makes sense. As the clutch lifter arm is so easy to move. But as mentioned it was OK for 2 miles but not now. Any more thoughts would be helpful as this doesn't make sense at all to me.

Hello, if everything else is ok theres only the cable left . apart from the clutch pressure plate and thrust pin. are they ok

Barry

It seems unlikely but has the push rod lost its hardening on the tips and wearing away? Not likely in miles I suppose but a short rod might cause issues after a short mileage because there is some extra lost motion when the alloy box warms up. So if the take up is marginal when cold it might be lost when hot.

Some owners put a small ball bearing at the end of the rod to reduce oil running along it (or something like that...). Maybe the PO did this and shortened the original rod (or the mushroom stem)? Again, without the ball there might be enough motion to lift it when cold but not when hot.

Hi Nick,

You should always try and fit a 1/4" (6mm will do) ball bearing between the mushroom and push-rod as this stops the mushroom trying to pick up and spin the push-rod. If you have tried all the obvious you might need to strip the clutch again. What can happen is the plain plates can get stuck on the hub where the inner tabs slideagainstthe hubslots. Make sure all the edges are free from burs or grooves and each plate slides freely. Don't be afraid to grease these parts as although some may get thrown onto the plates, it's not normally a problem.

Regards, Richard.

Many years ago I had a pushrod lose its hardening on the end and it was astonishing just how quickly I lost all movement.

I ended up chopping a bit off a 2BA screw (sitting beside the kerb on the Derby ring road) and using that as a spacer which was enough to get me back to Brum.

Well done Nick and thanks for sharing the info with us.

That's another another little quirk for the memory bank.

George

Previously nicholas_reeves wrote:

I would just like to update everyone who was kind enough to give invaluable help and advice. I have found out that the push rod was wearing so quickly it was loosing all adjustment within a couple of miles. Just as Ian Soady had suggested. It was the last thing I thought it could be. On closser inspection I found that the clutch end was burred making its removal quite difficult. At least all sorted and a valuable lesson learnt, expect the unexpected. Many thanks again to one and all. Regards. Nick.

Nick is it possibleyou have theadjustment up too tight if itswearing therod end? Thereshould besomefreeplay in the releasemechanismor itwill continualybeengaged androtate withverylittlelube around. Also the rodshould be able torotate freely in theshaft when not active.

I knowwe all look foreverythouon clutchrelease movement but one tip I hadfromGeorgeCwasthelever fulcrum on atwin wasshorter thanon aleverfor a single7/8"verses1". Hewouldoftenredrill levers toget thebestmecahnical advantage, Trustyou areall fixed up now.

Best regards

Jon

When it happened to me I was running a special consisting of an ES2 engine / gearbox in an Enfield frame. As the Enfield engine / box were shorter than the Norton items, the constructor of the bike (not me) had dispensed with a primary chaincase and merely had an outer covering the works. This did mean the primary chain was in a right state and the clutch had also suffered so adjustment was always a problem. I eventually rebuilt the power train into a rigid Norton frame and it made a very nice bike.

The point re lever pivot distances is well made. You can normally get 7/8" and 1 1/16" items - the former gives an easy action but reduces the throw. 7/8" levers are good for front brakes as they give extra leverage.