Jubilee Clutch overhaul

When I got this bike the clutch was stuck- I had assumed that this was simply the plates binding due to lack of use or incorrect oil but No! the lever simply couldn't be pulled even though the cable was new; something had clearly seized solid. I also suspect that the cable is incorrect as it had insufficient slack to remove it.

I thought the obvious place to start was the timing side clutch operating mechanism.

Timing side case

 I started by removing the kickstart- a bolt rather than the expected cotter pin and followed this with the gearchange lever. The case cover is held by 5 screws which could be easily undone but the case it self will not come off unless you remove the footrest and exhaust.

Kickstart and gearchange removed

Footrest is a standard thread unscrew anticlock. Note remnants of oil flowing from motor

The footrest is attached by a 12 point hole in the rest  which fits onto a hex bar on the bike rather than splined shafts I expected. Both sides were worn and I will need to find some way of tightening the fit between bar and footrest as this isn't affected by the bolts allowing the rest to move regardless of how tight the nuts are.

To remove exhaust loosen the two bolts securing the bracket to the silencer from the rear

and GENTLY wiggle the pipe steadying it at both ends and especially around the bend at the head end to prevent fracture. Eventually the compound weakens and the pipe can be eased out of the head. This seems a very poor mounting mechanism.

Cover removed- the gearchange indicator mechanism came off with the cover but this seems to be a 50/50 chance. In future make sure you hold the splined shaft as you remove the cover to make sure that this happens and that the mechanism doesn't come apart with sections on the case and cover. Note springs engage in split plate (below kickstart bush). Base of spring, cupped washer  are aligned to open the indicator shaft hole and the bottom. The nut on the gearshaft (in crankcase half) has to fit into the large ring at the base of the spring

Case contents exposed- nasty bits of old gasket. Note nut on gearshaft bottom right that has to fit into the indicator mechanism spring.

 The cover then came off with a blow from a mallet. Its a very complex contents including the gearchange indicator which was missing on the exterior. I'm not sure how this works but will reinstate it if I can.
The gasket was in a sorry state- torn, bits missing and bodged up with silicone. This bike has a tremendous oil leak... I had mentioned the oil puddle to the PO when I was bidding- "Oh I overfilled it" I was told- a tall tale repeated when I went to collect. Why he bothered to make up this daft story when he was upfront about the clutch is a mystery to me but there's nowt so odd as folk eh? Given the state of this ridiculous attempt at a gasket and the fact that the bike empties its oil over the garage floor in 2-3 days I don't think the leak can have been a mystery to him! In fact I tried to drain the oil tank before starting this work but it was empty already!- most of its contents now in my drip tray. The other point is that this case has clearly been visited in the very close past- there is fresh grease (a tremendous amount of it) so I suspect there have been several attempts to fix this clutch problem already and it may prove to be more recalcitrant than expected.... I did solve it eventually and the cause of the problem is visible in the  picture above if you want to try and solve it yourself...otherwise read on....

Operating the lever showed that the actuating arm did move so I removed the primary chaincase to see what effect this was having on the clutch. Drain oil by unscrewing level check plug and drain screw at lower right hand side.

Drain oil from primary chaincase- this is the level plug- oops. Mind you there was a load of oil above the level so the bike was overfilled. 

This case has obviously been repaired (badly) in the past. I suspect this is ordinary GRP which isn't suitable for oil immersion, but if its one of the "quiksteel" alumium repair or equivalent epoxies then it might be OK. Doesn't seem to be leaking.

No need to remove exhaust for this side, just loosen the footrest (anticlock surprisingly) and withdraw it slightly to get some room

Chaincase removed

At first site this looked OK. However the clutch was surprisingly loose and wobbled.  Operating the cable produced no effect on the clutch at all so I decided to investigate further.
The cover plate centre nut (adjuster) was removed, the adjuster plug came out with it. I then unscrewed the three clutch springs and cups by unscrewing the special split nuts. There is a proper tool for this but I just used a large screwdriver.

Removing adjuster plug and the three clutch springs and cups.

 Having removed the centre plate I could just lift the clutch plates out. They all looked fine, loads of material on them and not too much chipping around their "ears" I kept the stack in order with a cable tie and laid it aside while I looked at the centre.

Centre

 The clutch centre was surprisingly loose, tightening the centre nut whilst holding the centre in a clutch holding tool improved this no end- remove the pushrod though so you can get a socket on the nut. This process still didn't help the clutch basket wobble but this is probably a different fault and didn't seem too bad, perhaps a repair that can wait? I thought it best to try and fix the operation first, so I refitted the pushrod and operated the lever-  still no movement so I returned my attention to the mechanism itself.

Clutch operating system- cable removed, fragments of old gasket!

 Having removed the cable I could operate the lever by hand and it was clear that as well as moving in a radial direction, the lever also slid easily in a vertical direction. When it slid downwards the operating arm fouled o the alloy moulding of the gearbox inner cover. This prevented it from rotating fully. The operating arm has a spring referred to as a "pinion return spring" and this is certainly one of its jobs- although the clutch springs themselves probably pull everything back more effectively. However it seemed that its second function is to hold the arm up so that it cannot jam on the case moulding. The spring itself looked compressed (picture above). I removed the operating system to check all was fine inside- there is a retaining ring at its base which can be tapped round. This meant I could check that the ball bearing was inside (it was) and that the arm rotated easily.- all seemed well  apart from the spring above. I extended the spring and refitted everything checking the ball was still inside and tapped the retaining ring around again to tighten. The extended spring is visible below.

Clutch operating mechanism, note extended spring holding up the operating arm. The castellated retaining ring is visible at the base of the operating mechanism housing

I refitted the cable- which was very difficult as I suspect its the wrong cable but eventually it went in. I got extra manoeuvering length by cutting a half cm off the adjusting mechanism in the lever. Operating the lever now produced a smooth movement of the pushrod! I refitted the clutch plates and centre plate, screwing the springs down (I couldn't check that pressure gave a no slip engagement yet because I cant run the motor with no oil so I tightened them down fully and them backed of by a turn)  I screwed in the adjuster until the centre plate started to move and them backed it off a half turn and tightened the lock nut. Operating the lever showed that the force required wasn't excessive and the cover plate moved smoothly and squarely. I will adjust more fully when the motor is back together and I can road test for clutch slip.

Finally I cleaned all the horrible silicone off the covers in readiness for refitting when I get (or make) a gasket.

I wasnt sure how to align/refit the gear change indicator mechanism. I got these pictures from the owners club which helped to see how it should go back together. Note that the part-cup washer (13) fits inside the base of the spring with the wider section uppermost. Rocking part of the indicator mechanism (11) has to slip between the arms of the spring (12). I dont think there is a specific alignment position as the movement is one rock per gfear change so you can simply attach the pointer at the relevant gear on the outside of the case.

Having refitted it the cases slipped together nicely. I don't have the indicator lever yet so I put a pen mark on the indicator shaft-and checked that I do get a movement when I change gear. All  good!
I will order an indicator lever and I'm advised to fit a small washer underneath it so that it can move independently of the gear change shaft. . I was also surprised that there seems to be no diagram showing the position and lengths of the chaincase screws in the parts book or manual. The screws in my cases have been changed over the years and consist of a mixture of slot-head, cros-head and Allen cap screws; some seem very short. I inserted them as found but I'm not sure that these are all the right length or in the right holes.