C: Clutch Refreshing Vincent Twin Clutch seals and pieces

[Bill Thomas]

If the P/case is off, I think the best way is to use Mole Grips that has a chain built on, They are for sale,
If you grip the engine Shocker, It's like holding the crank shaft, Rest the end of the tool on a bit of wood to stop it turning, I also use this to do up both crank nuts, If you use a lock tool on the chain, The springs on the shocker move, When doing the crank nuts up, So you don't get the right feel, I think. Cheers Bill.

 

[Bill Thomas]

 

[oexing]

I am not quite sure about the working of the complete assembly in all details, but there are some reports about loose nuts . Obviously that can happen even after torquing them down a lot. I guess in these cases the not so perfect fit within the carrier/gearshaft spline joint was a very sloppy push job. So even if you do not look at shocks from the chain you will agree that any play, say two thou in the spline , will produce an orbiting of the carrier around the gear shaft of a 2 thou circle at each revolution of the clutch assembly simply by the chain pull. Whenever you do up the C 20 nut it will load all components onto the PD 21 spacer and ball bearing. BUT between all components there are places that will not do that 2 thou orbit like the carrier on the spline so there will be wear at that spot and soon there is no more nip in the stack of parts. That may explain why some nuts stay put, some not so. I would not dare to trust into the amount of nip in this place plus the safety wiring through the nut and shaft but apply some very mild Loctite on the thread like 222 . That is like a nyloc nut effect, you do not want a stronger type on all of the fine, big thread, you´d be very challenged to undo the nut later.
Basically there should not be a lot of a twisting action on the C 20 nut apart from loosing the preload due to axial wear in places. But I suspect there may be some negative input from the bronce bush in the C 13 clutch carrier. How is that bush lubricated , hardly ever ? So when the setting of that servo system is somewhat uneven between the two shoes I could imagine some very high sideload on that bush cum C 20 nut , a lot of friction in consequence and possibly loosening the nut from side loads. Certainly I cannot prove that point , just adding to the discussion, no practical experience on Vincents so far.
Anyway, whenever there is some wear within the spline any heavy tightening of the C 20 nut will not be a permanent fixture, so you might as well just screw up finger tight and add some other safety means like Loctite on the thread. I would not trust the safety wire alone.

Vic

 

[nkt267]

I bolted a bar to this and block it against the footrest spacer

 

[timetraveller]

Paul, it will depend upon whether you have your gearbox assembled yet. If you have then you can put it in top gear and block the final drive sprocket with a piece of wood between the teeth on that sprocket and the casting with a stud through it next to the sprocket itself. If there is not gearbox and not final drive sprocket then you will have to find another way.

 

[Peter Holmes]

I am not quite sure about the working of the complete assembly in all details, but there are some reports about loose nuts . Obviously that can happen even after torquing them down a lot. I guess in these cases the not so perfect fit within the carrier/gearshaft spline joint was a very sloppy push job. So even if you do not look at shocks from the chain you will agree that any play, say two thou in the spline , will produce an orbiting of the carrier around the gear shaft of a 2 thou circle at each revolution of the clutch assembly simply by the chain pull. Whenever you do up the C 20 nut it will load all components onto the PD 21 spacer and ball bearing. BUT between all components there are places that will not do that 2 thou orbit like the carrier on the spline so there will be wear at that spot and soon there is no more nip in the stack of parts. That may explain why some nuts stay put, some not so. I would not dare to trust into the amount of nip in this place plus the safety wiring through the nut and shaft but apply some very mild Loctite on the thread like 222 . That is like a nyloc nut effect, you do not want a stronger type on all of the fine, big thread, you´d be very challenged to undo the nut later.
Basically there should not be a lot of a twisting action on the C 20 nut apart from loosing the preload due to axial wear in places. But I suspect there may be some negative input from the bronce bush in the C 13 clutch carrier. How is that bush lubricated , hardly ever ? So when the setting of that servo system is somewhat uneven between the two shoes I could imagine some very high sideload on that bush cum C 20 nut , a lot of friction in consequence and possibly loosening the nut from side loads. Certainly I cannot prove that point , just adding to the discussion, no practical experience on Vincents so far.
Anyway, whenever there is some wear within the spline any heavy tightening of the C 20 nut will not be a permanent fixture, so you might as well just screw up finger tight and add some other safety means like Loctite on the thread. I would not trust the safety wire alone.

Vic

I think you are absolutely spot on, I have had the C20 nut come loose on me at least twice in the last 10 years, last time in the middle of Dartmoor this year just past, on both occasions the C45 spring tang had sheared or fatigued and the C20 loosened itself, as it loosens you loose your clutch lever and cannot change gear, I always do the C20 up FT as described in post 67, as you suggest, I think a weak Locktite would be beneficial, next time I have the clutch down I will try it, just hope that I do not get stranded in the meantime.

 

[craig]

The most important step in Vincent clutch assembly is -
Apply a liberal coating of some non-setting gasket cement to the internal splines, and fit the carrier to the clutch shaft.

This assures an hydraulic lock on the spline fit and minimizes the problems associated with "racking" the 8 pieces of clutch/gearbox being held by C20 onto G3 shaft.
Choice of sealant product.
Where to apply.
How much to apply.
all very important.

 

[oexing]

Good point, Craig. But instead of non-setting gasket cement I´d better go for a weak setting type of Loctite , 222 may be suitable. 274 is a bit tougher. Anyway, a good idea would be to do a test with some spares for getting a feel about the pull required to disassemble some day. The added up area for the Loctite is not really small so a low strength type will be allright. I do believe now that in case of a loose fit within the spline can be overcome with some Loctite for keeping the C 20 nut in its place (plus some Loctite on its thread as well ) .

Vic

 

[greg brillus]

Geez I hope I'm not the one who has to disassemble your clutch next time.............. Loctite is great stuff, but only where it's really needed..............The main problem why most folk don't do the C20 up tight enough is because the nut has a very limited amount of hex available for a socket to get good contact with. You should really machine the mouth of the socket down so you get a full hex contact, then just do it up with a 1/2 inch rattle gun. Ok a figure like 60 Ft Lb's for those who prefer the touchy feely thing. No such figures in the books to say yes or no..........Well guess what.............Most old Brit bike owners shop manuals also have little or no torque figures in their specs either, so I'm using a common sense approach and years of experience to tell me what I feel it should be. If the inner splines on the C3/1 shoe carrier have too much backlash on the spline there is a good chance the OD of the hub will also be badly worn, this will cause a very sloppy chainwheel, even if the bushes/seal have been renewed.............Do yourself a favor, contact the Voc spares co and buy a new one. Both problems solved. Don't forget to tighten that nut fully...........I strongly recommend you DO NOT USE LOCTITE ON THAT FINE THREAD. You will seriously regret it if you do........Good luck.

 

[vibrac]

Does no one stuff washing line in the plug hole before tightening up nuts any more? Or has every one got a spindryer