Possibly modifying a heavy clutch on my 99?

Hi Tom

I have fitted a belt drive to my 1960 M 50, and it has a diaphragm clutch incorporated, and is also not as light as it could be, so I await your answers with interest.

Kind Regards John O

John, I was surprised you did that because my Model 50 clutch with the standard set up is a one finger job. Yours must have been leaking oil?

I might have suggested to Tom that he tries his 99 with one less drive and plain plates. If he's not riding it hard he might just about get away with it.

Otherwise a new clutch cable and try slightly loosening off the pressure plate screws (X3) just a touch. All trial and error.

Happy New Norton Year.

(Just enjoying a bottle of Norton red wine)

First off - check your clutch lever. If you have an AMC gearbox, the distance between the centre of the lever's pivot screw and the centre of the nipple should be 7/8". The other thing you could try is fitting an extra couple of plates (one plain, one friction) to bring the clutch up to 650SS spec (more plates=less spring pressure required). If you do this you will need to check that the final plain plate (the one that sits under the 'half' plate under the alloy pressure plate) cannot run free of the clutch basket when the clutch is pulled in Your clutch must be the later type to do this with the outer tangs on the plain plates. You will also need the 650's alloy pressure plate or have yours skimmed down in thickness ( by the thickness of the two extra plates) otherwise no advantage will be gained. I'm assuming that your cable's well oiled and the clutch lever pivot isn't worn. Fitting RGM's needle roller thrust bearing conversion to give an even lift to the pressure plate may help too. Finally, use ATF in the primary chaincase.

Cheers,

Ian.

It is also possible to improve the profile of the operating cam. My PO did it and mine is easier than most. I think details of the improved shape have been posted here before.

I do make sure my gloves are not to tight or my hand cramps up in traffic.

The correct 7/8" pivot levers are available from several suppliers: AMC Ckassic Spares do good quality ones: http://www.amcclassicspares.com/

and cheaper versions are available from places like this: http://www.sparesforclassicmotorcycles1.co.uk/ although I have no experience of their parts.

A new nylon lined cable lubricated with thin silicon fluid improved mine a lot. I have also drilled the gearbox mounting plate and oil tank bracket to allow a better cable run into the box. A bit drastic!.Avoid the heavy gauge clutch springs that are useless even for an Atlas .Try the RGM ones.File off the ledges that form on the outside of the spring cups.Borrow a dial gauge to set up the springs to lift evenly.I can pull my 99 clutch in with one finger (Just!) and I am older than you are.I have never wore my underpants on the outside of my trousers.

As far as I remember, Venhill recommends not to lubricate nylon lined cable sleeves.

Fritz

Hi Fritz, Do not use oil, use thin silicon fluid where there are Nylon linings.

Previously ian_allen wrote:

First off - check your clutch lever. If you have an AMC gearbox, the distance between the centre of the lever's pivot screw and the centre of the nipple should be 7/8". The other thing you could try is fitting an extra couple of plates (one plain, one friction) to bring the clutch up to 650SS spec (more plates=less spring pressure required). If you do this you will need to check that the final plain plate (the one that sits under the 'half' plate under the alloy pressure plate) cannot run free of the clutch basket when the clutch is pulled in Your clutch must be the later type to do this with the outer tangs on the plain plates. You will also need the 650's alloy pressure plate or have yours skimmed down in thickness ( by the thickness of the two extra plates) otherwise no advantage will be gained. I'm assuming that your cable's well oiled and the clutch lever pivot isn't worn. Fitting RGM's needle roller thrust bearing conversion to give an even lift to the pressure plate may help too. Finally, use ATF in the primary chaincase.

Cheers,

Ian.

hello Now ATF is no good in your primary chaincase it buggersthe rubbers inside the clutch LUCAS Harley Davidson Clutch lubs is ten times better and it cools and grips

Previously tom_mcewen wrote:

As I'm over 70 I find I get painful hand fatigue from my bog-standard 99 clutch which puts me off traffic riding. Is there any way to change to a lighter clutch, say a diaphragm spring type, or any other suggestions? I really want to use the bike I've had for 50 years properly. Many thanks.

Now on eBayHydraulic clutch too cable mod which is fitted on the gearbox were the clutch cable fittingwas short cable fit to clutch arm the rest is all hydraulic fitting from 29 quid look it up on eBay motorcycle parts yours anna j

Previously anna jeannette Dixon wrote:

Now on eBayHydraulic clutch too cable mod which is fitted on the gearbox were the clutch cable fittingwas short cable fit to clutch arm the rest is all hydraulic fitting from 29 quid look it up on eBay motorcycle parts yours anna j

Hi Anna,

Any URL?

Fritz

The issue is that the clutch lifter on AMC boxes has the wrong ratio, and lifts the clutch too fast, particularly the initial bite. The AMC bikes got 7/8" pivots on the brake and clutch levers, which helps a bit. Some people regrind the clutch lifter arm to soften it. Can anyone give a link to a drawing or other information to show what profile?

My bike has a horizontal box (and almost exactly the same clutch), and I have fitted 7/8" pivot clutch lever. It is a light and very sweet clutch. There is nothing to stop it being just as nice when that clutch is mounted on an AMC box

Paul

Previously paul_standeven wrote:

â?Can anyone give a link to a drawing or other information to show what profile?â?

Here it is: http://atlanticgreen.com/ndnsclutch.htm (see Atlas Actuator)

Fritz

Previously Fritz Wettstein wrote:

Previously anna jeannette Dixon wrote:

Now on eBayHydraulic clutch too cable mod which is fitted on the gearbox were the clutch cable fittingwas short cable fit to clutch arm the rest is all hydraulic fitting from 29 quid look it up on eBay motorcycle parts yours anna j

Hi Anna,

Any URL?

Fritz

Thank you Anna.

Fritz

Previously Fritz Wettstein wrote:

Thank you Anna.

Fritz

hello will this be of any use to you or anyone else within our club this hydraulic kit screws into the gearbox where the old cable use to be is has a short cable to attachto the clutch arm so everything the same inside the gearbox no mods needed the outer has a slave cylinder to lit the cable the rest is a hydraulic pipe that fit right up to the handlebar and clutch lever is of hydraulic type the only thing is you may have to change out the adjuster at the gearbox end now do have fun with this , yours Anna J

I recently received an email from Phil Hannam (unfortunately no longer a club member), he has fitted a RGM belt drive to his 650 Dominator. Apparently the fitting was not that easy, but, he considers it well worth it To quote:-"I now have a superlight clutch, non dripping chaincase, and very smooth transmission." The cost was 550 Pounds, however, he highly recommends it. (My Spanish keyboard does not have a Pounds" key!)

p.s. If anyone wonders why Phil has left the club, it is due to his experiences, and opinions, of the 961. I can say no more.

Previously tom_mcewen wrote:

I now have the correct 7/8inch pivot lever and the teflon-lined cable, with good results. My Norton manual has very poor detail on the clutch, only showing the lightweight twin clutch which is different from my 1957 Dommi 99.

What I need to know is 1) What is the correct number of plain and lined plates: I have 5 plain steel plates plus four with cork friction sections both sides, then the outermost is lined on the inside and plain on the outside where the alloy pressure plate presses on it. The basket containing the clutch has cork inserts, so the innermost plate is the first plain steel one. 2)what you suggest for the optimum setting for the three springs to ensure grip-without-slip, but not to cripple the rider's left hand, as taking the primary chain-case off to readjust the three springs is pretty tedious. 3) how important is oil in the primary chaincase? A good deal seems to migrate along the gearbox mainshaft, which I've filled with SAE 30 as per the book. Sorry to witter on but you guys have the know-how! Many thanks.

Hello Well you have the 650 clutch and not a model 99 clutch which has four of each and has a shallow basket, and as fillingyour case with SAE 30 Witch will not do the job you need it to do, however, there is a lubricant that can will make your clutch bite or slip as you move the clutch lever and lubricate and cool your clutch and protect your clutch all at the same time . what is this you may ask,! well its LUCAS Clutch lube MADE for all wet clutches like Norton Triumph a Bsa and our friends Harley Davidson and you can get this on eBay, And Tom keep on wittering that'swhat this forum is for, So good luck with itall yours anna j

I have used ATF in primary drives for many years without problems. My reasons are two:

1. Automatic gearboxes have clutch packs very similar to the multi plate clutches fitted to our Nortons, and with similar Ferodo material. So if ATF is OK for them it's OK for us.

2. ATF has anti-frothing additives which keep it stable.

It's also nice and thin which admittedly can be problematic if the chaincase seal is not perfect.....

Previously ian_soady wrote:

I have used ATF in primary drives for many years without problems. My reasons are two:

1. Automatic gearboxes have clutch packs very similar to the multi plate clutches fitted to our Nortons, and with similar Ferodo material. So if ATF is OK for them it's OK for us.

2. ATF has anti-frothing additives which keep it stable.

It's also nice and thin which admittedly can be problematic if the chaincase seal is not perfect.....

hello ATF attacks the clutch rubbers try Lucas Clutch oil it cools and lubricates and no Clutch slip, and ATF is corrosive so wearrubber gloves when using it,it's not nice stuff yours anna j

Hi Tom , From your early comments its clear that its NOT a 650 clutch but earlyer with inserts in the drum and cork linings possibly a mixture of parts. Anna means well but does not always read things through. I would hang onto the plates for a while as you may well finish up with a later clutch anyway!!.