Clutch woes

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Jun 16, 2005
Hi chaps,
clutch drags (can't get neutral etc) and also slips when given a bit of hard work to do.

the current set up is 5 bronze plates ( with a spiral groove ) .120", four steel plates .075", and a pressure plate .100" the primary case was filled with 20/50.

any tips ?
Roy - Kent, UK
20W50 is too thick for the primary, I have use Harleys Primary chaincase oil and have heard that you can use automatic transmission fluid also. The clutch plates sound like they are contaminated with oil which causes them to stick at low rpm and slip at higher. You can take them out and clean them to remove any oil and that should help. I would also inspect the center hub that the plates sit on, if this is worn and groved then the clutch plates will stick and cause all sorts of clutch problems.
I use ATF in the primary, and just enough to allow the lower run of the chain to dip into it. My experience with the bronze plates are they easily become saturated with oil. Cleaning will help, but this becomes an annual ritual. Your plate measurements are very good, so maybe a good cleaning and lighter oil may help. Also consider a clutch hub seal as it may be caused by gearbox oil contaminating the plates. This is available from RGM or "Dyno" Dave Comeau.

The dragging may be adjustment or it may be a worn clutch hub center. Examine the hub center next time you have the plates out. There should be minimal notching of the surface the inner splines slide on. Norton switched to a hardened clutch center around '72-'73, but they probably used whichever was in the box until the old one's were gone. The old style Barnett plates were supposed to be very hard on the clutch hub.

As far as adjustment, I don't follow the manuals direction of screwing in the adjuster until it touches and then back off one full turn. I find a half-turn sufficient and allows a little more lift at the spring. I also shim the clutch pack for easy clutch pull.
Check to make sure the circlip behind the basket is correctly installed.
Make sure the hub nut is not overtorqued. If you are going to remove the plates for cleaning anyways, you might as well check the hub for grooving, check the circlip, and it will give you a lot of peace of mind.
You should also be able to hear the "jangle" of the clutch plates when you lightly tap the kickstarter.
ATF Dexron 2 (the old Chrysler type) works fine in the primary and in the front end.
Thanks for the advice,
the plates are soaking in petrol (gasoline) a new -hardened - centre has been ordered from Staffs. and the old centre has been sent back to Cadbury's (Hershey's) Engineering dept. for evaluation.

I had that exact same problem with my 75 - 850 .. I replaced the bronze plates with Surflex plates . You will have to add one or two steel plates in for spacers as the thickness of the new plates will be marginally thinner. Get rid of that damn 20 / 50 and use transmission fluid . I add the 7 oz just as the manual calls for and have had no problems what so ever in three years since i changed. You will never look back

Enjou your riding

The original clutch setup on my well-abused 850 mk3 is still going string, after about 60K (based on spurious speedo readings, the cable breaks with monotonous regularity...), and I've got the hang of setting it up with *just* the right amount of play to stop it from slipping. How much is not tangible, it's based on feel and comes from experience and much gnashing of teeth. If it drags a little, I don't mind. If it slips when i'm giving it the berries it does get a little embarrasing.

Three things have proved important to this.

1) I clean the plates every year in petrol, as they do get oily.
2) I use ATF in the chaincase, filling it up 'til it just starts to leak out of the filler hole.
3) Adjustment is a right royal pain in the ass until you've got the hang of it. In fact, I use the book's standard set-up and work from there if it still slips/drags/both. Practice makes perfect.

I do have the o-ring mod for the clutch actuating shaft, but I've never got round to fitting it due to the usual Norton owner's "prioritisation of problems" conundrum.

norton clutchitis....british cycle supply in nova scotia canada has the pushrod seals that will help...biggest problem is trans fluid leaking onto clutch plates....go to the ontario norton owners website..i have an article on how to setup the primary chain there which will help out a lot of woes in that area....get ahold of derek wilson...he is a regular poster on this site and discuss the matter of properly setting up the installed diaphram height on the clutch which is als critical ...good luck barry
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