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.

Jubilee Seat Pan Repair

Thought I'd start  by looking at this collapsing saggy, saddle...

Seat badly fitted and sagging

The seat fitted to this bike was poorly fitted, this became clearer on removal...

Seat cover was attached by extensive pop-rivets
through perforations in the seat pan sides.

Seat cover peels back loosely, note non-std and
now disconnected switch fitted beneath-
hints at previous security step as the bike has no ign key.

Seat foam deteriorated and collapsed

Cover removed to reveal seat foam

The seat pan itself was very rusty and extensively cracked. There were signs that its been patched up before.

Cracks to rear of seat, strengthening pieces added in past

Cracks at mid point of side. Only one rubber button present on this seat-
there should be one in the same position on the other side.

Seat pan front: Note damage to left side and destruction of rubber holder.

The seat is attached to the bike by two vertical stays at the rear that fit over the suspension upper mounting studs and two rubber bushes at the front that fit into metal holders beneath the seat  and accept two protruding studs on top of the frame side tubes. Note that in this seat only the right bush (as shown in this picture) is present, the left hand bush holder has been destroyed although the bush itself was still on the bike. There is also quite a bit of damage to the front of the seat, and in fact the metal here had been thinned by corrosion.

Overall this pan was in bad condition, really I would fit a new one if one were available. Of course anything made by man can be reproduced but the cost of having a custom made seat pan is expensive. As this pan has been repaired once and is already on the verge of viability, there was nothing to be lost by my attempting to repair it. 

My fabricating skills are not extensive, this pan really demands new parts be made and welded in but this isnt going to be practical at my skill level. Instead I will try to reinforce where possible by welding strengthening plates  over the stress points. The front of the seat has worn too thin and is too badly corroded so I was forced to cut that out and replace with a new piece of metal.

New metal welded in to the seat front

 The rubber retainers needed to be replaced and I found that bending sheet metal around a 20mm steel electrical conduit was just about perfect.

Metal sheet folded around 20 mm conduit

This was sliced to create bush holders

The bush holders made above were then trimmed with metal snips before welding them into place beneath the seat pan on the new metal I had installed. This is quite tricky as they need to be positioned very close to the side of the seat. It took several attempts and even now I'm not sure that the bushes will be in exactly the right position (!), but hopefully good enough for a positive and secure mount.

Completed pan (underside) with new bush holders fitted

Seat pan upper side

The welds on this pan are clearly not pretty, but they will be invisible and mostly covered with foam and fabric. The pan is at least solid now even though its a patchwork of reinforcing plates. The cross seat strengthening strip was also installed by a previous owner and seemed a good idea, so in a belt-and-braces approach I reinstalled it onto welded studs.

I gave the pan two coats with Jenolite rust converter. I like this stuff because its water based and seeps everywhere water has penetrated and so treats rust in inaccessible places. I let this dry over 15 mins and then rinsed off any excess with methylated spirit. This degreased the pan and also penetrated into all the crevices removing water and replacing it with the more volatile alcohol. The meths can be removed easily with a hot-air gun- or as this happened on a rare sunny day in Surrey, an hour in full sun!

The original pan was painted blue, so I gave it two coats of smooth Hammerite, This is a lighter colour than the original blue, but all bar the underside will be invisible anyway. The blue on this bike is probably a hard to get cellulose paint but fortunately the modern Vauxhall colour Polar Sea Blue (pearlescent) is a pretty good match so I gave the underside of the seat a coat of that before fitting the foam.

Underside painted with vauxhall polar sea blue

... topside left in hammerite blue.

Here is the finished pan- I am aware it doesn't look great but its solid and the rust has been controlled.

I sourced a new foam through the owners club and a new seat cover from Ebay. There were surprises with both when they arrived; the seat foam being rather too large and the cover having an unusual inner fillet, so both will need further investigation before I can get on with the fitting.
I since found out that the inner fillet is normal for this pattern of seat cover. The outer layer hangs free at the seam to give a neat edge to the saddle whilst the inner fillet is clipped and glued to the seat pan edges.  Unfortunately the seat cover I received was simply too small. Its quality was great and although it fitted the length and width of the foam, its depth was simply too little - it covered the foam but not the seat pan and there was no way it could be pulled down to attach to the seat. In fact it would fit perfectly only if you left the foam out entirely! For reference the distance from beading to beading (ie that around the saddle and around the base) was only 4 inches, and the inner fillet only 1 3/4 at its widest. These are both way smaller than the torn cover I removed so it will have to go back.

Cover depth from beading to beading at the rear of the saddle- 4"

Inner flap depth 1 3/4"

I will order a replacement from the owners club- this presumably will fit the foam they supplied.

Norton Jubilee restoration: Introduction

This is the Norton Jubilee 250 I acquired via eBay. 




 According to the log book its a 1959, but it spent some time off road, being re-registered in 1971. At that time it was assigned its original registration which presumably means that it must have been linked to a DVLA record that went back to '59. However the previous owner sold the registration (sacrilege!) and the bike was assigned an offensive 1971"T" registration in 2015. The bike has many features which suggest its a later bike; the seat is of the bolt down rather than clip on variety and the the pillion footpegs ought to be the flat pattern but in fact they are round. The frame number 94953-17 suggests a 1960/61 manufacture. This is a bit of a puzzle given that DVLA records presumably go back to '59. However many early bikes did have parts replaced with those from later models and I will have to get to grips with it when I eventually try to get an age-related registration.

The bike does need restoration- it runs and actually sounds remarkably good, but it is a bit smoky on start-up suggesting that the valve guides may need attention. I was also warned that the clutch was stuck when I bought it. This is true, but it turned out not to be simply a case of stuck plates as I had expected. In fact the whole mechanism is jammed. I also discovered on pick up that the front forks are stuck in the compressed position and the lights  don't work and the headlamp isn't aligned properly. Also leaning the bike on the side stand leads to a pretty significant puddle of oil so I suspect there is a case of wet-sumping in there as well. In addition there are numerous other bits and pieces  and many fasteners that seem to be wrong with several metric nuts that ought to be Whitworth. So plenty of jobs at least to get on with. I will get around to these and strip the bike later, but to start with I thought I would tackle the seat as the poorly fitted cover is obvious and unpleasant. As I'm currently fitting this work around my Lotus restoration (see my other blog, "Lotus excel resto") the seat should also give me a short self-contained job that I can fit in while I'm waiting for parts!