I copied this over from the 'For Sale' section as it will probably get a wider audience here...I hope Neil doesn't mind...Ian
['Hello folks, I have an issue with the kick starter on my 1948 M20. It was extremley difficult to start earlier this year due to oher issues previoulsy reported. I wonder if this excessive kicking has caused problems. I noted that quite often the kick starter arm would move through its arc of motion but would either not move any of the internal gearing (engine did not rotate) or at the very least it turned a small amount at the end of the arm's travel. The arm has resistance in its motion but just doesn't turn anything? It now seams to have failed in some way with the arm not coming back up. I guess the return spring has failed in someway or come off some retaining peg/mount. I can manually pull arm back up and kick it again as before (with the lack of engine rotation) but mostly stays down. What is very odd is that a couple of times the arm has returned, but not often. Has anyone any thoughts? seen it before? Am i looking at taking gearbox out?
cheers Neil']
email (option): nlhclarke@gmail.com
email (option): ian@wright52.plus.com
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
email (option): ian@wright52.plus.com
Could it be the gearbox mainshaft nut loose and gradually unwinding, and pushing the the internals away from the kick start, have you had to adjust the clutch cable recently.
Could it be that this 1948 gear box has an earlier WD kick start spring - that might be wider ?
Just a thougt.
I'm assuming the clutch is not slipping and there's no unusual noises in the primary drive!!....Ian
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.
Many thanks for all the suggestions as always.
Cheers
Neil
email (option): nlhclarke@gmail.com
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
email (option): ian@wright52.plus.com
Hello all,
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 Neil
email (option): nlhclarke@gmail.com
On a WM20 box there are 4 awkward 1/4 bolts to remove. The larger nut is part of the gear change mechanism and doesn't need to be removed. Ron
email (option): ronpier@talk21.com
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 !
Cheers Neil
email (option): nlhclarke@gmail.com
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
email (option): ronpier@talk21.com
The thickness of the outer cover gasket isn't critical...What condition is the Kickstart quadrant rubber stop in?....Ian
email (option): ian@wright52.plus.com
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
email (option): ian@wright52.plus.com
Different clutch as well with no special tools needed?
email (option): jeremy@clogmaker.co.uk
Hello again
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?
Cheers Neil
email (option): nlhclarke@gmail.com