I took my '64 Jubilee for a short test ride today after fitting a new battery. I could only select first and a second gear. I was sure I had checked that all gears selected before I put the engine back in the frame but perhaps I did not.
Looks like a gearbox strip down is required but before I do that does anyone know why only two gears are selectable? I come up against a hard stop when trying to move the gear lever to third gear.
I seem to remember I had several attempts to put the gearbox back together and on the last attempt things just slipped into place. I don't know why it worked that time and not before.
Lastly, do I have to dismantle the clutch side to free up the gearbox main shaft or can the main shaft stay in place while I take apart the gearbox from the kickstart side?
Have you tried with the engine running? Also check if your gear lever is fouling anything (can’t remember if it can) but it’s a common issue on other makes.
Not sure how much you can dismantle without undoing the clutch, but you should be able to see what is going wrong.
I’m stripping mine shortly with the engine in the frame to replace the sleeve gear, so may be able to offer further comment!
Dan, thanks for the suggestions, Yes I tried with the engine running and I checked the gear lever was not fouling on anything.
I am going to take off the gearbox cover without dismantling the clutch side to see if there is anything obvious as it is such a pain to strip the clutch side. I may still have to remove the clutch at some point.
There seems to be no further downward movement of the lever after second gear so it might be the selector is in the wrong place.
I'll give an update when I have some news.
I’ve had my early gearbox apart a few times it’s pretty much impossible to put that together incorrectly, I’ve only had the front cover of the late type (vainly trying to fix oil leaks!) but will be stripping it to fit a new sleeve gear as soon as I’ve finished timing the ES2. I can’t remember if you can put the selector in the wrong position? I’ll post the extracts from my original manual
Dan, many thanks (again)!
Not got around to taking the gearbox apart yet, enjoyed doing other things in the good weather.
I have the manual as an .PDF but thanks for the images anyway.
The first thing I will check is the alignment of the foot-change ratchet alignment mark with the mark on the small pinion. If that is correct the other possibility is one of the 3rd or 4th gears may be reversed stopping the selector fork from engaging/moving the gear but I think this is unlikely.
I found that the footchange selector ratchet was not aligned correctly with the small pinion on the selector shaft, hence the 'lost gears'.
The manual specifies aligning the mark on the selector with the mark on the pinion. Sounds easy but the first issue was identifying the mark on the selector as it is partly obscured by a locating plate and looked at first glance like a manufacturing blemish! Secondly, the pinion mark was in fact two punch marked 'N's, so I take it that the pinion tooth between the Ns is the locating one for neutral. If this was not obtuse, then not being able to see either mark on assembly was a real problem. The parts are behind the gear cover plate on assembly.
My solution was to find the position of the selector relative to the pinion without the cover plate in place, take the selector plate off without moving it, mark the two peaks of the pinion gear that mesh with the selector (those either side of gear trough marked by the Ns) using correction fluid ('liquid paper'), refit the selector and loosely fit the end plate, check the alignment by peering through a hole in the end plate using a torch to see if the mark on the selector is aligned between the marked teeth of the pinion.
Before I sound too smug, having assembled fully the gearbox and I can now select four gears but there is a mysterious neutral beyond fourth gear and first is hard to select. I may still be one tooth out on the small pinion !!
I will do a road test before I decide if I need another go at aligning the selector.
The manual seems light on advice.
I used to tell friends that Haynes manuals were similarly challenged. They follow an inverse law. You get 20 paragraphs on how to change a bulb and only a few lines for a difficult task usually starting with : "First remove the engine.....".
I’ll be doing mine next week, I’ll let you know how I get on! Sounds like you are on the right track.
Dan, many thanks. I am interested particularly in the alignment mark on the selector plate as I am still not convinced that what I am seeing is the correct mark. The pinion is marked clearly so identifying the position of the selector plate is critical to success.
I have decided to strip the gearbox again to have one more go.
Dan, I took some photos of the pinion and gear selector alignment marks. The selector plate mark is obscured by the locating plate so I have moved that to one side. The 'mark' appears to coincide with the hole in the selector plate. This mark is hidden when the locating plate is in position!
I am hoping you can confirm that you have the same alignment mark on your selector.
Even if the alignment marks are correct there sees to be some potential on assembly to get the alignment wrong resulting in too few gears or at the other extreme, a false neutral after 4th gear.
Dan, having just assembled my gearbox wrongly again I have had a eureka moment. I did not realise that the selector alignment plate is detachable from the gear lever shaft! I should have looked more closely at the diagram you posted.
No wonder I could not see the alignment marks. By disassembling the selector mechanism I should be able to offer up the selector and align it with the pinion before fitting the locator plate that obscured the alignment marks previously. This was not obvious before as the shaft (28 in the diagram) seems firmly fixed in the gear lever shaft (32). I will have to investigate how to get them apart.
Hi Dennis, nothing surprises me anymore!
I'll not be stripping mine until next week now, I'm showing mine at the local fete and don't want it in bits, as it is there's nothing inside the chain case! I want to replace the sleeve gear so it will be a complete strip of the gear box and I might as well do the bearings while I'm in there.
Thanks anyway and good luck with your repairs.
After three more goes yesterday I might have set up the gear selector correctly.
As I suspected, fitting the selector shaft without the gear change ratchet does allow me to see the 'alignment' marks, the problem is that the pinion marks (the two N's) still only give an approximate alignment; one of three possible gear teeth. The alignment has to be exact otherwise the selector won't work properly. A single mark on the pinion would have been much better.
Frustratingly, you can only test the selector alignment with the gearbox assembled fully (without oil). If the alignment is wrong it is a full stripdown including mainshaft nut and tab washer.
It looks like the top 'N' mark, at about 4 o'clock, is the correct one to align with the selector mark, with the lower 'N' at about 5 'o clock.
No wonder I thought the selector shaft was part of the gear change assembly. I had to hold the gear change lever spline is a vice (lead jaw protectors) and drift the centre shaft out using a bolt screwed into where the gear indicator goes. The shaft has two o-rings as oil seals and they are a tight fit even when lubricated. This causes a problem on reassembly. When the selector shaft is in place in the gearbox the gear lever shaft has the fitted over it. I had to tap the gear lever shaft spline on the front face gently until the selector shaft protruded past the spline end; only then could I get the outer casing on.
Lastly, I found fitting the kick start return spring before fitting the clutch lifter and specifically the large circlip made fitting the spring easier as it does not foul the circlip. You might want to withdraw the clutch cable entirely from the casing as it can easily stop the inner plate going back in place.
DThanks for that Dennis, I’ve just stripped mine and wish I hadn’t!
Anyone got any spare late selector forks?! - Looks to have been brazed, to be fair I had all four gears but a bit of a whine and rather too many metal flakes in the bottom of the box! Mind you this is the engine that had a wooden cam chain adjuster!
Ouch, what a mess. I hope you locate a spare.
I now have four gears but the change is clunky. I used heavy grease to lubricate that gear selector shaft and that was a mistake. I thought it would help the two oil seal o-rings do their job but it just gummed up the shaft. The shaft and seals do require lubrication but thin silicone grease might have been better.
Really sorry to see that Dan, although not listed in their spares catalogue Norvil might just be able to help. Do you know of anywhere else that can provide late Lightweight gearbox and clutch spares? That said I wonder if Hamlins at Bridgewater could 'recondition' your damaged ones? I would welcome any feed back if you go down that route - you never know what the future holds with a Lightweight! is your Navigator on the road? If so do you fancy meeting up on the bikes for a coffee? My Navigator is behaving at the moment so always taking it for a run!
Sadly the Navi is still only partially assembled, and the Jub gearbox is in bits! If I can’t get any selectors quickly I may accelerate the assembly! But am up for a coffee if I can get anything running! the ES2 trials just needs timing. At least my scrambles bikes are behaving for the moment! Remind me where you live?!
Near Crewkerne, I seem to remember you saying you aren't far away. Good luck with the parts search - much as I prefer the later gearbox spares supply is a real worry. As for the ES2 - there is nothing quite like a morning spent grappling with a timing disc, feeler gauge and a cigarette paper setting up the timing....at least it is a single!
Can you provide me with the part numbers you need?
With the numbers I will check all my sources here in Northern California.
That’s very kind if you it’s 048185, but hang fire for a couple of days, I may have found one over here.