C: Clutch Refreshing Vincent Twin Clutch seals and pieces

timetraveller

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Thanks for the advice Martyn but note that I wrote that I put the piece of wood near to a spoke nipple. Actually I ensure that the piece of wood is actually under a nipple and I have never bent a nipple or broken the piece of wood. I am somewhat bemused by this thread. With the mod I recommend I not only do not get oil into the clutch, it is actually dusty in there. As for things coming loose or getting thin through wearing; well I have never found a loose nut when the spring was intact or found a shim significantly worn. As I wrote above, unless there is something I do not understand here then all that tightening the nut is doing is ensuring that the gearbox main shaft, shim, bearing centre and shoe carrier rotate as one. As for micro rotation of the shoe carrier on its splines leading to wear and using Loctite to prevent it, I despair. Vic is clearly a competent and experienced engineer but the thought of having to dismantle a clutch by the side of the road or at a rally with any grade of Loctite on the splines gives me an attack of the conniptions.
 

stu spalding

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If difficulty is experienced removing shoe carrier C3 from the mainshaft, try drilling and tapping it 5/16 BSF so that a bolt screwed in will bear against the clutch drum, avoiding the C2 screw holes, and will act as an extractor. Obviously, this should be done with C3 off the bike. Cheers, Stu
 

oexing

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Once again, there are VERY different kinds of Loctite and the 222 is a very low strength type. You don´t get low strength bearing fit types so I suggest this 222 which is just like a nyloc nut on threads. That should be acceptable with its shear strength. I´d prefer to have splines safe for the small penalty of needing a simple puller to disassemble - will be a very unlikely case when all is as it should be from the start. There are a lot of bikes with taper fit sprockets, dynamo rotors and so on. You typically don´t carry heavy pullers on the bike for roadside repairs - and you will not need them with all likelihood provided the engine was assembled as it was supposed to be.
To be clear, as long as the splines in carrier plus gear shaft are good fit you will not need Loctite there to prevent loose nuts and no high torquing down will help permanently with sloppy fits. But I bet this will be a rare case today with old parts and I did not trust new spare parts in this respect. Instead I lasered all shaft splines and machined them for absolute minimum push fit to new spares.

Vic
 

craig

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I use all the Loctite products on a daily basis performing maintenance on Ohlins suspension products. Disassembly and reassembly daily. I understand Loctite value and use in my shop.

I would not recommend Loctite for any position on this Vincent twin clutch assembly except maybe for the C20 nut. I don't personally use Loctite in this Vincent clutch assembly, but certainly in other areas of Vincent assembly.

You will need a product in the Vincent twin clutch spline for hydraulic lock, but not Loctite series, in my opinion.
Cheers
Craig
ClutchSeals3C20bLargeMod1TV.jpg
 
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bmetcalf

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Vic, I'm going to try the Loctite 222 on my splines and compare it to Hylomar for disassembly. TT, I'm going to read your post thoroughly and see what I can do with my clutch parts to follow your recommendations. Yes, I shouldn't need anything on the splines, but I also shouldn't touch my clutch at all since it has been non-oily since I got the bike in 1980! :D

Kevin Cameron, writing in Cycle World, talked about fretting on Yam TZ750 cranks that was cured by using Loctite where it wouldn't ordinarily be needed, to fill small gaps that eventually allowed flexing and breakage and in our case loose nuts and sprockets. This would influence me to use it, even if not needed for oil retention.
 

Peter Holmes

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Just to cause a bit more consternation; with my mod I use a very small amount of non fling grease on the splines to enable easy removal and prevent any corrosion. It does not work its way into the clutch. Oh dear!
I think you are probably wise to lubricate the splines, wear can certainly occur to a spline joint due to the forces that it is subjected to, apparently my VW T5 has an inherent spline drive shaft problem that VW had to address with a modification, I am not sure what caused the problem but I think they said that it was fitted dry and corroded. I have great admiration for TT being able to form an accurate O ring recess with a hand held grinding wheel, I am sure that if I attempted that it would be a complete and utter disaster.
 

timetraveller

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Thanks Peter. With the photograph I did clamp the shoe holder on the bed of a mill and used the valve seat grinder in the quill chuck. However, the first one I did, 50/60 years ago was done with the same hand tool as I used to remove the dogs from the gears to give me double back lash on third and top.

Bruce, let us all know how you get on. I still do not understand what is implied by the nut coming loose with the spring tang still intact. I wonder if people are referring to the fact that if they dismantle things they can tighten the nut further than they could a few years before. That would indicate wear somewhere, possible the shim. I have never come across it but possibly others have.
 

oexing

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Norman, the only reason for loose C 20 nut I see is axial wear at some place in the train of components on the clutch gear shaft when you do up the nut real hard plus a sloppy spline that admits micro friction wear at these places. You are lucky having components with good fit so you have never been faced with this trouble obviously.
I´d be interested in cases where the nut has unscrewed dramatically: What kind of securing means was selected in these cases, safety wire or this wire spring end as designed by Vincents ?? I guess this only happened with very sloppy spline fits ?? --- Seems I repeat myself a lot here . . . .
Looking at drawings of the clutch, the C 20 nut has a ground o.d. for a reason, a bush of the clutch shoe carrier acts on this diameter. Now that bronce bush has practically NO lubrication so what does that mean in the long run ?? Just thinking: Is there a chance with a poorly set/ worn clutch shoe assembly and uneven loads on the carrier that this bush transfers heavy sideloads onto the C 20 nut ? If so, under every hard acceleration there is a high torque load on the servo clutch and with high friction and side load due to no lubrication of the bush there could be a real twisting action onto the nut ?
When no lubrication anywhere in the dry clutch is essential why not better use some lubricant-free bush in this place like some types from IGUS , see link below ? I´d expect much lower friction coefficient and safer operation regarding the loosening of the C 20 nut , Permaglide teflon/graphite bushes another option.
For extending the useful life of sloppy splines I just looked up Loctite types: The 221 seems to be even better than 222 for some joints, same low strength but very low viscosity . Reason for choosing Lotite settling types is the dry compact film can take high loads as opposed to squashy Hylomar that I´d expect to walk out of the joint in time. For assembling all new perfect parts I´d take chain spray plus MoS2 powder for preventing any wear therein. MoS2 can take extremely high loads so great in this application and chain lube will stay there safely.
The VW spline trouble is most likely a bit different as this joint is in motion and does long axial strokes like in front engine - rear drive shafts. These joints require hd grease lubrication for sure.

Vic
IGUS bushes

Loctite 221
 
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