Hi Guys
I am now the proud owner of a 1942 WM 20 this bike had not been running for over 23years, surprisingly it took little effort to get it started. The only problem I had was the fuel taps leaking which I have fixed.
But after running it today there was a pool of oil with a felt like substance under where the sprocket comes out of the gearbox, have got a pic but can't put on hear.
Any ideas of where it is comming from?
Have got a vid of the Bike but does not show oil leek.
https://youtu.be/_hU1InPHlvY
I am on the Gold Coast Australia
Thanks Kev

email (option): windburner1@gmail.com

Hi Kevin,
has the gearbox lost oil level ?
If so, most likely the box is leaking on the main shaft, near the clutch.
You should check the bronze bush there, it may be worn.
And you can change the main bearing with one that has a sealing on the outside.

But first you could check your crankcase breather. They sometimes spit out oil.

Thanks Michael
Will check it out. Little bit disappointed that this has happened cause the bike was ready to get a roadworthy then registered to use on the road, will get it sorted out soon enough. There where 3 motors and gear boxes that came with it in pieces so I have got a good supply of parts. I am capable of doing the work myself if pointed in the right direction.
I am away next week on holladay will get onto it when I get back.
Kev

email (option): windburner1@gmail.com

to stop the engine there should be a valve lifter which is a small lever on the clutch lever side the cable goes to the side of the tappet box and lifts the exhaust valve the gearboxes are prone to leak as there it not really a oil seal on the input/output shaft looks a nice bike

email (option): roger.beck@node6.com

Kevin did you remove the crankcase drain plug and the primary case level plug before you started the engine. It would most likely have 'wet sumped' over that 23 years and could have drained through to the primary case and then sprayed out behind the clutch?? Ron

email (option): ronpier@talk21.com

When you get back, try the 3 oils trick.
Get some Penrite or Royal Purple Gearbox oil which are a purple colour.
Put some green 20W50 in the engine
Put dextron ( pink ) in the primary.
There should be a cork tube on the main shaft behind he clutch and a big cork ring around the sliding plate behind the clutch.
Both of these should be soaked in warm water over night before assembly then once assembled leave overnight again for them to dry out.
These are supposed to keep the primary oil in the primary case and the gear box oil in the box.

They don't by todays standard but did by wartime standards,

Any way, dain the old oils. don't forget the sump fill up everything start the engine, run the bike for 10 minutes or so then park it over an old sheet or blanket or some white adsorbent paper.

Look at the colours of the oil drops.

When the engine is cold drain every thing, noting the qualtity and colour to see if engine oil has contaminated it ( 99 % chance ) and of course check all the oil levels to see which ones have dropped.

There are virtually no oil seals on your bike, most oil control is by slingers.
To work properly the clearence between slingers and cases or shafts is critical and most M20's will have worn well beyond that limit.

Mine will fill the primary in about 1500 to 2000 km.

Also a blocked or sticky breather will over pressurise the crank forcing engine oil into the primary till it pours out the back.

email (option): bsansw1@tpg.com.au

Its my gear box...
Had some time to have a good look today, checked the oil level in the gear box could not see any in there, while i was filled it up I notesd a grease nipple put into the top plate so I suspect that the gear box is full of grease.
After filling the gear box up I gave it a run oil was comming out of the clutch leaver,kick start,gear change leaver and of cause out of where the sprocket comes out.
Will have a look around when I get back from holiday to either have it rebuilt or rebuild it myself.
Kev

email (option): windburner1@gmail.com

Hi Kevin,

When you say "after filling the gearbox up" to what level are you talking about because the locations you mention (clutch, gear lever, kick start and mainshaft are pretty much the high level marks and oil will leak from these areas if over filled. In fact oil will weep from these areas when oil is at the correct level when in operation. Also oil will leak from the mainshaft behind the sprocket if the bike is left on the side stand if a non sealed bearing is fitted.
Lastly remove the grease from the box, it's not designed to run with grease as it will be clogging up oilways.

Hope this helps.

email (option): bsansw1@tpg.com.au

I don't now why but my farther in law allways does this, one day when I went round to see them he had his Panther 100 out and was filling the gear box up with grease, but you can't tell him any different. I will pull the gear box out and check it over.
Kev

email (option): windburner1@gmail.com

G'day Kevin,

Grease in your father in law's Panther may well be correct some old boxes used grease or semi fluid grease but your M20 uses engine oil. Straight 50W if you can find it or 20W50, don't be tempted to use gear oil it's not good for the bronze bushes.

Some AMC and some Burman boxes were grease filled.
BSA made all their own boxes with the exception of the bolt up A10 box which was bought in.
So their care & maintenance is different from every thing else.

The warning about gearbox oils is a bit out of date.
All modern boxes have syncro cones which are brass.
Back in the 60's & 70's gear oils would be marked "syncro safe" if they could be used in a modern box however they dropped that long while ago.
Truck gear oil is a different matter it contains a lot of sulphur with reacts with the copper in brass & bronze so should be avoided.

AS you are going to pull the box you will do well to replace the bearings with sealed ones, leave both of them in and dont use metal sealed bearings
The kickstart quadrant bearing which is steel will most likely need replacing.
As far as I know there has been no successful attempts to put a seal on this shaft.
You can machine a seal to the gearchange.
You se a thing called a "quadring" which is basically an O ring made in an X cross section, CBA & Bearing Services both stock them.

As you ar on the Gold Coast, pop in to a BSA Club of QLD meeting.
A lot of knowledge there and a lot of M20 owners all willing to help get another bike back into active service.
Mike Riley is a member ( Mikes Bike Parts type Mike Riley ) and it wont hurt to get to know him. Bill Green is local M20 specialist and keeps most of what you will need in the way of standard parts.

email (option): bsansw1@tpg.com.au

I fitted an o ring to the kickstart assy. but not by putting a groove in the shaft...I decided that with such a heavily loaded component that may result in a stress failure at the groove...

I made up a quadrant bush (steel) in two pieces and fitted them to the casing with a gap between them to take an o ring...

It worked well but I have never repeated the experiment...When I left the Toolmaking game the hardening and grinding facilities went west with the job... ....

However, it would probably be just as successful using some flame hardened silver steel....Ian

email (option): ian@wright52.plus.com

Hardened bush ?
I have always unsed plain mild steel for the bush so it wears in prefference to the kickstart quadrant.

email (option): bsansw1@tpg.com.au

Don't think splitting the bush is a very good idea, two seperate bushes are not as strong as one large one, so it will increase the stress on the allready very weak and overstressed aluminium part of casing which takes the bush.

Think a groove close to the end of the shaft would be better, the diameter is large so think it will not weaken it much, at least not as much as the much smaller part of the shaft which takes the kickstart lever and cotter pin.

Personally I never found the need for an O ring, I pick out the best bush I have and smear the shaft with high melting point grease and it does not leak there till now.

I also always glue the bush in the casing with green loctite as they tend to come loose and turn in the casing and so wear out the aluminium.

Cheers, Michiel

G'day Trevor and Kev,
Congrats on the '42 M20 Kevin, they're a great bike. Thanks for posting about the qld BSA club, Trevor. I've just moved up to Brisbane and will head to the QLD BSA owners club meeting, I hope to see you guys there. It'll be good to meet more M20 fans.

Cheers, Matt

email (option): Matthew.j.croucher@gmail.com

You won't see me there as I am in Sydney ( sort of ) but I know most of the Qld boys. good lads & always willing to lend a hand.
Normally I would be at the BSA National Rally which will be in Beau Desert this October but this year I am farm sitting so I will have to miss the first one in 12 years ,

email (option): bsansw1@tpg.com.au

['Don't think splitting the bush is a very good idea, two seperate bushes are not as strong as one large one, so it will increase the stress on the allready very weak and overstressed aluminium part of casing which takes the bush.']

You may be right Michiel...I only did it once and it worked OK for the time I had that bike...

When rebuilding boxes I always fit a NOS quadrant and bush and that seems to be fairly oil tight...I don't really mind a small oil leak either!

On the subject of cracked kick start bush housings I haven't had much success with welding...In fact I wrote off two covers that way, being unable to restore them dimensionally after welding...

For a while now I have done the repair below...I turn down the boss and fit a steel ring over it to support (and contain) the cracked boss...

Dimensionally care must be taken to ensure there is sufficient clearance for the kick start spring and a lathe large enough to 'swing' the cover is needed..I can do it on my Harrison 300 which has a 'gap' bed...Ian

email (option): ian@wright52.plus.com

G'Day Trevor,

I went to the meeting today and met Kev and some of the QLD club. Seems like a good group and lots of knowledge there on M20's, so I think I'll have to join up.

I missed the BSA national rally last year in Clare as I was up in Bris. Hopefully I'll be able to go to the one this November. You'll just have to take your bike out to the farm and give it a good ride offroad to make up for it!

Cheers,

Matt

email (option): matthew.j.croucher@gmail.com

Glad it worked out well.
I run a workshop out of the landlords old house.
He lives 600meters from the workshop.
The rent is to give him a hand on the farm so I usually do a dozen or more miles each weekend which is why my M20 does not have a wet sumping problem.
Most of the Qld boys know me so they probably gave you the appropriate BS warning.
However I will be at the Victorian All British Rally this year.
It is their 40th so a big event and there will also be some sort of a dedication to Ric Strange who was the driving force behind the national rally who tragically died last year age 63.
Fred & a few other will be driving down and I am sure they will find room for you & your bike if you can come .
Other than that we host the National in 2017 which will be at Cowra, almost riding distance for you.
Then the BSA Internationl rally will be in Victoria in 2018 so you will be able to meet a few of the owners not lucky enough to live in Gods Gift to motorcyclists.

The last know crated WW II surplus WM20 was found & sold in Brisbane a while back.
The DAS took over the warehousing for the Defence Departmnt and down the back of a warehouse ( that is now a housing estate ) was a brand new WM20 and a WLA.
I think it was the late 80's , early 90's I am sure the locals will recount the story over a few XXXX's

email (option): bsansw1@tpg.com.au

I have now got everything sorted out on my M20 it is now running well, I do need a pillion seat and pegs I will get them wen money allows.

email (option): windburner1@gmail.com