Clutch Basket Movement?

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Bruce MacGregor

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Hi, I just installed a new counter shaft sprocket for 520 chain on my 850. After I reassembled the clutch basket using all the original shims back in their original position ! found that the clutch basket will move in & out about 1/16 of an inch with the nut tightened up. I dont remember that this is normal and the instruction books say nothing about any amount of allowable movement. Should I disassemble everything again and re check the shims or is this normal.
Thank You
 
Bruce,
is the mainshaft moving laterally as well?
If so it may have some end float.
If not something is wrong.
Marshal
 
Is the whole clutch moving, centre as well or just the outer ? It sounds as if the drum may be moving on the bearing ?

Are you talking about end-float or run-out if you push one edge and pull the other ? Clearance in the bearing means that even with a new bearing fitted, the wobble can be more than one might expect.

Has the clutch location circlip displaced or split ? If the mainshaft is all up tight at the other end then it can't move. The clutch centre can be pulled up tight, even without any shims (but of course the alignment would be out).

In view of the fact that the centre nut pulls the centre against the circlip, there can only be movement there if the circlip has moved or the nut isn't fully tight? (Is the clutch location spacer correctly fitted over the circlip ?)

I think that dismantling and checking would not be a bad idea (and it's all good practice ! :) )
 
It looks like the motion is that the main shaft has the 1/8" axial displacement.
There is no wobble of the clutch basket from side to side.
So, I guess I need to find what is not controlling the main shaft axial position.
Any Ideas
 
Bruce,
there should be some movement as the shaft needs movement slightly or it would bind.
Someone here could tell you how is acceptable.
Marshal
 
Ah, Thanks for reminding me that the main shaft is located with the nut / bearing position on the inner cover of the tranny.
That photo reminds me that I need to make sure the main shaft nut has not backed off, before I open up the primary again.
I wonder if that could be the cause of Netural being harder to locate recently?
Thank you
 
Hi, I opened up the transmission outer cover, removed the clutch mechanism and the main shaft nut fell out.
I re did everything and used some loctite on the main shaft threads this time, torqued to 70 ftlbs.
There seemed to be no damage to anything. Clutch seems to work great.
I find it amazing that everything ran OK with the nut off the main shaft!
Last year I found that sometimes I would have to re adjust the clutch adjustment nut on the handle bar to get the clutch to free up when stopping at a traffic light.
That is the only indication of a problem that I had that was probably related to the floating main shaft & clutch.
If I had not opened up the primary to change the counter sprocket and noticed the end play, I would be still driving it that way.
Thanks to all who answered wih ideas of where to look.
Bruce MacGregor :roll:
 
I think 70 ft/lbs is a bit too much for that nut. I recall that torque spec being a manual error. I think I did mine at 50 or so.
 
The older Norton boxes didn't have a nut on the mainshaft (it wouldn't have been possible with the worm type actuating mechanism). They did however have a bronze thrust washer internally and the end-float had to be shimmed.

Bikes with this level of technology have an amazing ability to keep running when things are not quite as they should be.
 
Coco said:
I think 70 ft/lbs is a bit too much for that nut. I recall that torque spec being a manual error. I think I did mine at 50 or so.
Click to expand...

The torque figure for the nut at the clutch end of the mainshaft ("clutch-to-mainshaft nut") is indeed listed in various manuals as: "70 ft./lb." which is generally considered to be too high.


Bruce MacGregor said:
I opened up the transmission outer cover, removed the clutch mechanism and the main shaft nut fell out.
I re did everything and used some loctite on the main shaft threads this time, torqued to 70 ftlbs.
Click to expand...


The torque figure for the nut on the gearbox end of the shaft ("mainshaft nut") is "40/50 ft/lb", not 70 ft./lb.
 
There is a spacer behind the clutch hub 060747 with a relief on one side that goes over a circlip. This is called the clutch locating washer. If this is over torqued it can shear this clip. I suppose it could also happen from sitting for an age. If it goes it sounds like a muffled pop and things will be loose. It is a fairly easy and inexpansive fix. Old Britts recommends that you shy away from the stated torque specs and take it to 35flb and use some locktite.
I don't know if this is your problem, but it a reasonal place to look. Don't ignore it cause you will burn stuff up back there if not addressed.
 
From the 850 Work shop Manual " Engage top gear,apply the brake and tighten the gearbox main shaft nut to a torque reading of 70 lbs/ft".

I'm guessing that the last time I had the tranny open, that the clutch assembly / primary were not in place when I torqued the main shaft nut. I vagely remember holding the counter sprocket some how and tightning the nut. but probably not to sufficient torque.

How ever, the nut on the clutch basket should not be tightened past 40 -50 lbs/ft because it can destroy the cir clip, stop/locater on the clutch side of the main shaft . regardless what the manuals say.
 
Bruce MacGregor said:
From the 850 Work shop Manual " Engage top gear,apply the brake and tighten the gearbox main shaft nut to a torque reading of 70 lbs/ft".
Click to expand...

Yes, the manual does say that, but it's contrary to the information given in the torque specification section, also Mick Hemmings in his gearbox rebuild video says: "I notice it says 70 [ft./]lb in the book-which does seem like a great deal of torque, although I have known them to come undone..." so he recommends "a spot of Loctite" and he certainly doesn't appear to tighten the nut anywhere near to 70 ft./lb. in the video.
 
Well it's going to stay @ 70 lbs with loctite unless I have to get in there again!
I'm guessing that 90% of the Nortons out there are @ 70 lbs also.
Also 70 lbs is not much considering it is fetching a bearing inner race up against a step in the main shaft.
Rear axle is 80 lbs to lock the inner races up against the axle spacers with about the same size bearings.
 
Bruce MacGregor said:
Well it's going to stay @ 70 lbs with loctite unless I have to get in there again!
I'm guessing that 90% of the Nortons out there are @ 70 lbs also.
Click to expand...

True enough, I expect.


Bruce MacGregor said:
Rear axle is 80 lbs to lock the inner races up against the axle spacers with about the same size bearings.
Click to expand...

Yes, although the rear axle is somewhat larger in diameter than the threaded end of the mainshaft, and it isn't hollow.
 
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