restoration 1940 bsa m20

My latest purchase arived today. A 1940 BSA M20.

Dont know a lot about old bikes really but it has had the engine re-built but the timing needs to be set up and the carb fitted aswel as a few other jobs. It is missing the speedo and bracket and i am not sure what else.

Does anyone know if any history can be found on the bikes service at all? I believe it was registered in Holland after the war but other than that i do not know.

Any help would be appreciated

Nice... not jealous at all

right nice ol' bike that

finally got a chance to have a good look at it this weekend. Found a few markings on it, the contract plate on the rear mud guard, a few military markings on the engine, the name on the tank "Marly"?.

The brake handlebar lever clamp is broken so will have to keep an eye out for one. Found remains of green paint inside the oil tank cap and residue of it elsewhere.

Looking at a pic of your engine number, I notice the stamp mark in an oval, JLO. This has come up before, it was a German engine manufacturer. It could be that they reconditioned engines for the occupying British Army after the war, or were overhauling engines from captured British bikes.

Hello, the best source for WD bikes related information is the BSA m20 site. Just have a look you will find a lot of information about m20 stuff.

Guy

Nice... not jealous at all

I am.... I love these things

Apparently their fuel economy is the same as a truck but who cares.....

I bought a Ural, slowly comming in pieces

Apparently their fuel economy is the same as a truck but who cares.....

I would like a truck that could give the fuel economy that I used to achieve with a WM20 ........... anything between 60 and 80 mpg on a long run

Looking at a pic of your engine number, I notice the stamp mark in an oval, JLO. This has come up before, it was a German engine manufacturer. It could be that they reconditioned engines for the occupying British Army after the war, or were overhauling engines from captured British bikes.

It would be interesting if you are right, i might have to look into it.

Hello, the best source for WD bikes related information is the BSA m20 site. Just have a look you will find a lot of information about m20 stuff.

Thanks, seems like a good website, will definitely come in handy!

Just one question:

What diferent oils do people reccommend for diferent parts of the bike? I found the cork gasket has split in the chaincase ( have ordered a new one ) so it is completely empty. Also it would be good to replace the other oils, what oils are best?

New cork gasket arived and fitted for the chaincase.

I am currently tring to sort out the wiring. It has been fitted with electronic ignition and i am having some dificulty getting my head around it. There are several wires which i cant seem to identify on my wiring diagram form the manuals, a lot of them seem to be earth wires but i am unsure where the proper earth points should be.

(sorry for the bad images, taken with my phone, will try to take some better ones!)

With the points cover and case side removed to see the modern electronics inside. Nothing seems to connect to where the ht lead enters

From interpreting the wiring diagram i believe these wires go into these holes but it is not clear which goes into which hole, any ideas?

Most of the earth wires seem to have been connected together and earthed behind the bettery mount, is this correct?

Aparently the new electronics came with instructions but none were supplied when i bought it and i canrt seem to find it online at all so any help at all would be highly appreciated. Details like how to alter the "points" would be useful and how diferently the wiring acts around and including it.

cant tell you much about the electronic ignition but I can tell you the 2 wires with the bullet connectors on are the dynamo wires and the item with the 2 holes in is the dynamo part of the mag dyno,these are normally attached to a plug which fits into the 2 holes shown.try googling Sean Hawker for electronic magneto conversion,I know he makes them and may be able to help you

Nigel

cant tell you much about the electronic ignition but I can tell you the 2 wires with the bullet connectors on are the dynamo wires and the item with the 2 holes in is the dynamo part of the mag dyno,these are normally attached to a plug which fits into the 2 holes shown.try googling Sean Hawker for electronic magneto conversion,I know he makes them and may be able to help you

Nigel

Thanks for your help, i think a have a basic understanding now. Its good to know the supplier aswel, i may have to try contacting him if i have any problems.

Thanks again

think ill hang around n see how this turns out I do like my motorbikes

Hi Your electronic ignition looks suspiciously like the units Kirby Robottom do ??? May be worth giving them a call.

Regards

Andy

have you checked out the plans for the allied bike tour in Normandy 2014? we went in 2009 for the 65th anniversry and 2014 will be the 70th anniversary ,the aim is over 200 bikes together on the road for d day

have you checked out the plans for the allied bike tour in Normandy 2014? we went in 2009 for the 65th anniversry and 2014 will be the 70th anniversary ,the aim is over 200 bikes together on the road for d day

Unfortunately i do not have a motorbike liscence yet and i believe it would take longer than this to be able to ride this size of engine. Shame though, sounds like it will be quite an event!

last time a couple of lads did the recoed run on welbikes,so you could always stick on some l plates and join in,otherwise there is bound to be a spare pillion on the day

last time a couple of lads did the recoed run on welbikes,so you could always stick on some l plates and join in,otherwise there is bound to be a spare pillion on the day

Its still a way to go as yet but it is definitely something i would be interested in doing

Spent today cleaning and continuing to work out the wiring and i have gone as far as i can.

I took some better quality photos and have worked out a few theories on where bits go but i am not certain.

The wires below come from the magneto. Am I right in thinking that the red/brown like one connects to the battery (if so possitive or negative)? and the Blue goes to the Regulator? Or could it be the other way round.

One of the wiring diagrams sugests that one of these wires goes to the Regulator. So i took off the new regulator and all the wires are in use. One thing which i cant work out is that there are two wires ( Brown/Red & Orange) connected to the White and Purple wire which connects to the ignition switch on the headlamp. Is this right or does the brown/red wire connect to the brown/red wire from the magneto?

I am still tring to find out which hole these go into. When the cover to the dynamo is removed a red wire is inside connected to the hole on the left, does this correspond with the red covered lead ( Green and Black wire ).

I will get my bike out tomorrow and take a lok at the dynamo cables to see if I can give you some idea

Nigel

I will get my bike out tomorrow and take a lok at the dynamo cables to see if I can give you some idea

 

Nigel

That would be great thanks!

Another thing i am quizing over is the ht lead connector to the magneto. It looks as though a bit is missing from the metal piece. Is this the case? also any ideas on where the ht lead connects inside the magneto with the electronic ignition fitted?

Your charging system wiring is a complete mess. In my opinion, your best move would be to remove it and start again. The wiring on these bikes is pretty simple (although that said, yours has been made unnecessarily complicated by the fitting of electronic ignition instead of the self-contained magneto).

Your Dyno-Tec regulator is the type supplied by Sean Hawker. They're a good product and simply replace the standard regulator connections. The 'F' and 'D' referred to on the box are the dynamo connections. You'll need to remove the non-standard cover to see what's going on inside your dynamo.

The electronic ignition appears to be based on an old Boyer-Bransden backplate and pickups. These are OK (and were considered top-notch thirty years ago) but they are extremely sensitive to battery condition. You probably have a 12v conversion in order to run the Boyer. You won't get anything out of it without a fully charged battery in good condition.

The components that you're looking at are the old manual advance/retard cable connections which probably no longer apply as the Boyer is likely to have an electronic advance curve programmed in. Somewhere you'll have a black Boyer contol box (about the size of a cigarette packet) and this will need a live feed plus two wires from the pick-up in the magneto housing. There will also be a connection to an ignition coil which is probably tucked under the fuel tank and the HT lead will run from there.

You're not going to find a standard wiring diagram that takes account of these mods. My inclination would be to put a properly reconditioned magneto back on and then wire the bike as original (but with stop and dip lamp functions).

A phone call to Sean Hawker might not be a bad idea. He's a helpful chap (but the language can be a bit strong).

Where would you sugest getting a new magneto, dynamo etc from? There is a reconditioned Magneto for sale on ebay ending in just over a day at £180, is that fair? What sort of prices would i be expecting to pay

Where would you sugest getting a new magneto, dynamo etc from? There is a reconditioned Magneto for sale on ebay ending in just over a day at £180, is that fair? What sort of prices would i be expecting to pay

You really need to get the right type, correct mountings, direction of rotation etc. There is also a great difference between 'reconditioned' magnetos.

I'd suggest a post on the WM20 forum. Ian Wright at Ark Motorcycles who is a regular there can usually supply M20-correct items and is very fair to deal with.