Can stack height be too high

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Dec 5, 2007
Can the stack height be too high and if so what would be the result, Of all the issues i think the clutch gives me the most grief, still hard pull and cannott stop it dragging i had to force the second ring of circlip in with a drift so there is no way it cant be the height
i have checked the plates , no warping, the centre spline seems ok but i filed it smooth in case, actuator plate and ball seem fine, cable is loose and lined up with actuator, cleaned all plates with brake clean and can see no oil etc. ,is there a way i can make the clutch complelty release and work back from there, at this point id love a slipping clutch, i think if i can make the clutch complelty release i may be able to work backwards, i have trouble upshifting and finding neutral which is not surprising i guess as i need to hold fro t brake on with clutch in to stop running red lights, if i screw the nut in clutch in until it touches then back off half turn as per suggestions i get massive drag, if i was to keep screwing in and set a turn after touching should this not mean the clutch would be more than free when pulled, in my case it still drags?
Something unseen. The clip should just go in no tapping. Have you done figure 8's on a lapping plate? I rubber cement 220 down to 1/4 glass plate and support the glass on a Blanchard ground steel plate. Have you run with no cover to check the trueness with the clutch activated?Keep digging into it they are the best out there. What kind of oil in the trans? How tight is the primary chain? How straight is the trans alignment?
Dragging clutch was a big clue to me that my crank oil seal was leaking. Apparently, the clutch is very sensitive to oil level in the primary case - when the book says 7oz (200ml), it means it!

On advice from my local Norton expert, I changed from 40W oil to ATF in the primary. Clutch is happy, primary chain is happy, and I can tell if the crank seal starts leaking, as the ATF will turn brown if mixed with crankcase oil.

One thing about the plates and stack height - a friend of mine with a new Triumph (1050 Speed Triple) changed his clutch friction plates, and could not get the clutch to stop dragging. It seems the new clutch plates needed to be placed all in the same direction. Though the plates were not marked, careful examination showed the plates were stamped out of blanks one way. alignment in the same direction cured his problem.
What is the gap at the lever, and have you tried removing a plate?

Tried removing plate , no difference. ATF in primary, and no contamination on plates by other oil. rod seal fitted, primary chain adjusted correctly, alignment seems fine, Lucas 80/90gear oil in a freshly rebuilt box, gears change smooth as silk rocking bike without clutch, nearly impossible to upshift when riding, easy to downshift tho, new cable routed correct and smooth
I recently changed from trick Tomaselli levers back to standard Norton alloy levers and switch assemblies and it transformed the clutch action from quite a hard pull to a much easier smoother action. Do you by any chance have non standard levers, as I understand from a number of books that the Commando levers have a slightly better leverage ratio. Also I believe that some of the Dominators have a slightly enhanced leverage ratio at the operating lever to which the clutch cable is attached inside the outer cover. These issues will of course not affect slip or drag, but may make operation a bit easier.
Wait a minute did you say it shifts better one way then the other? This might turn into a thread about how to set a hair pin spring.
Have you tried a complete set of plates that you know work, how thick is the seal and how long is the pushrod?
Original levers, tried old plates no difference , I did notice the bolt holding the actuator was worn ,replaced that and now have easy pull, but still major drag no matter how much i try to adjust i cannot get the plates to totally disengage, Hair spring comment interests me tho, This is the spring on the pawl i am guessing, i think it is correct, new spring and just a fraction of clearance either side of pawl. I think the hard up shift is from the clutch drag, downshift slides in when revs are correct and there is no load, I plan to pull apart again tonight and try 4 friction instead of 5, this will destroy my stack height but should it not mean that the plates will be looser fit giving more room to completly release.
In reply to Cash, I will measure the rod while i have it apart but it was working reasonablly ok before the rebuild. Te rod seal is from Norval and the rod slides easily thru it ,
I seem to remember the backing plate in the clutch basket on my '69 "S" coming loose and causing a similar problem. I don't remember the details, but it seems Norton changed the manner of fastening the backing plate in a couple of years later.
fixed my mk11 interstate clutch which was slipping at riding speed and dragging at idle. Clutch center was notched and bronze plates splines that contact the center were worn. Replaced a couple of plates and the centre( with secondhand replacements) this fixed the dragging by allowing the plates to move freely on the clutch center.
fitted a Dave Comau push rod seal to prevent oil coming from gearbox onto plates this stopped the slipping.
Had no trouble ( with this part of bike) since. Cross fingers.
Thanks guys, With your great assistance another problem has been solved, clutch no longer drags, problem was new barnett plates, 3 out of the 4 steel were warped badly, 2 friction plates also warped, Solution ,toss the lot in the bin, dig out old originals sand friction and steel plates, clean up, put back together, Result, one finger pull, smooth as silk changes up and down, neutral selection while running a breeze,, As someone pointed out, it seems to be a lot of little things that make up a problem on Nortons, with your help i am learning to lok laterally at the issue and consider all the little things, Cheers guys, I am off for a run, no doubt to find another issue just around the next bend : :p
problem was new barnett plates, 3 out of the 4 steel were warped badly, 2 friction plates also warped

Rockyrob you're scarin me. I've just gathered in my 2 nortons after being in storage for 20 some years and one of the 1st purchases was a new set of barnett clutches for each machine. I'll definitely be checking them for warp now. I hope there is some reason for your warp-age and it's not a quality control thing with Barnett.
Clutch slipping/dragging problems on a Commando? Now there's a suprise...
You are using a triplex chain with oil, by your comments.
I would rccommend the following:-
1) Buy 'sureflex' clutch plates, not the bronze ones. The stack height of the clutch plates should fill the depth of the basket, to just below the groove, including the end plate. So you have just enough room to get the 'circlip' or wills ring in. The sureflex plates require a THICKER END PLATE than the bronze plates. (the end plate is the one with the gear teeth cut in it that the diaphragm spring operates onto).
2) Use ATF fluid in the primary case, or a light oil, 20 weight max.
3) Install a seal on the clutch pushrod to stop the heavy 80 weight gearbox oil fouling the plates.
4) Ensure you have the correct clutch pushrod actuating cam arm on your gearbox, which is the item your cable connect to just inside the gearbox outer cover. From memory the Atlas is different to the Commando one. You should use the one that gives the bigger movement at the box for a given cable stroke. I think this is the Atlas one. Ask Les Emery at Norvil to supply.
5) Ensure all is alligned good at the cable entry to the gearbox, when installing the above arm. Poor alignment here will cause you problems.
6) Buy a theflon lined 'Featherlight' clutch cable from Venhill, in Surrey. Ensure the cable route is free from obstructions. This will make a BIG difference!
7) If all else fails get a belt drive and run a dry clutch.

The spring should operate from about flat to just above flat when pulled.
My clutch does not slip or drag and can be pulled with one finger!
Good luck.
My clutch is stock, with the bronze plates that came with it when I got it. I originally used the spec'ed oil, but changed to ATF after my main seal leaked. An advantage to ATF is one can tell pretty easily if the primary is fouled with engine or tranny oil as the primary stuff would no longer be red.
I forgot to mention one point.
When you are backing off the clutch pushrod actuation screw, do not back it off half a turn. This is too much. Back it off just enough to clear with a touch of play, maybe a quarter of a turn.
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