There is clearly an issue with the box...Initially I would remove the outer cover to inspect the kickstart quadrant teeth, kiickstart ratchet assembly and the return spring...It's unlikely you will need to remove the whole gearbox I'd have thought....
I'm assuming the clutch is not slipping and there's no unusual noises in the primary drive!!....Ian
Cheers Ian, it looks like I started the thread in wrong place, thanks for correcting that. Always dodgy starting a post late at night after a few beers !
I think the clutch slip comment looks likely as has the feel/resistance i would imagine for such a thing? Is this adjustable or are the plates/springs on the way out? Am I correct to say its a dry clutch inside that domed housing over the clutch plates?
Ill take cover off the side of the box this weekend and have a gander to see how it looks ang maybe put a picture up if anything looks odd.
The clutch is a dry clutch...One possible problem (apart from the possibility of oil contamination) is that the fibre plates are badly worn...As there is no way for the dust that wears off the plates to exit the clutch dome eventually that can jam things up, particularly so if you have oil in there as well....It's actually worth stripping and cleaning the clutch every so often...I have generally done mine at 12 month intervals...
Original fibre plates are .093" thick when new...
Also check your clutch is set up correctly...With the clutch lever pulled fully in the arm on the gearbox should be vertical...You will need two special tools for the job...A spanner for the clutch nut and a spring compressing tool for reassembly...
In the Technical Section of the forum I've written a detailed article on most aspects of the clutch...It's worth a read....Ian
a quick question on getting tye gearbox outer cover off. It seems 2 types of gearbox available depending on engine serial, mine is xm20 5899. I have all facing screws off together with gear lever and kick-start. The cover is reluctant to move. I see there are bolts behind the cover on backside of box. There maybe 2 small and one large . Do I need to remove these?
Cheers Ron, your not wrong; they were bloody hard to get at. However, i only had 2 x 1/4 inch nuts and the larger one axial to shifting shaft which I didn't remove. The whole lot came off OK, once I noticed the circlip! When the cover was off it looks like I needn't have removed the nuts at the back of the box at all! They seem to just hold shifting mechanism in place.
The main find was a broken kick-start spring which I am on the hunt for next. I did notice no gasket, just cement. I read somewhere that the gasket was an important part of the clearance of some shafts. Is this correct. No oil seals were a surprise too !
Again I can't speak for the post war box but I think they are essentially the same. On the WM20 box the thickness of the gasket between the main shell and inner cover is important as that will alter the end float of the shafts. Ron
As it's a '48 bike have you got the later gearbox with the speedo drive?..If so the details for attaching the outer cover differ from the WD models....Ian
It looks like I definitely have a later gearbox. The speedo drive was a clue but not the full story. I used draganfly's site/drawings and ordered 66-3058 and the gasket from same drawing. Gasket was correct but spring slightly too big all round; 2 1/2 " rather than my 2 1/4" and thicker guage wire in its construction. I tried fitting it anyway but no good as overall depth pushed starter shaft off it's natural seat.
A couple of pics to draganfly and they identified my box as a 1950-62 possibly from A,B or C models? This might explain an earlier anomaly of it have 3/8" final drive chain and sprocketry instead of 1/4" ??
Ian yes the rubber bush was well shot and I got one them OK.
I reckon I might still need to get clutch off as I think even once starter working the clutch was slipping preventing decent action through to crank.
Do I need some special tool to get clutch off; spring presser of some type?
