Questions? Looking for parts? Parts for sale? or just for a chat,

The WD Motorcycle forum

WD Motorcycle forum
Start a New Topic 
Author
Comment
introduction

Hi, I have just purchased, what I am told is an old military BSA WM20 from the forties. It is 95% complete and was last registered in 1956 then put in a barn until now, but needs a total restoration which I am looking forward too. I am hoping that I can get the much needed information I will come across from this forum. As I am totally green to this bike I need to know what it is and when it was made. It was sold to me as an ex military but I can find no evidence in the paint work, it appears to have a silver tank with BSA stickers and the oil tank and toolbox appear as black with red pinstripe. I suppose it could have been repainted to get rid of the army green. The frame number is WM20 40715, the engine number is WM20 44444.Can anyone age or identify this bike ?

email (option): myf1@hotmail.com.au

Re: introduction

Hi.
Frame number 40715 was the 15,715th bike from contract C7287 which was for 17,000 bikes in 1940/41. 1,375 of these were sent to Australia. I calculate your tank census number to be C4357307. But if you email Henk on ahum@quicknet.nl he will probably send you one of his nice free dating letters.

Your engine is from a slightly later contract of which 1,175 were also sent to Australia.

It's a start! Ron

email (option): ronpier@talk21.com

Re: introduction

G'day Sacko,
Welcome to the forum, to confirm with Ron you can go to the frame numbers page on this web site and you'll see that quite a few Australian owners have bikes with frame numbers that are close to yours.
Generally engine numbers matched when the bikes left the factory but in Army service when an engine needed overhauling it was removed from the bike and replaced with one off the shelf that was ready to go so engine numbers rarely match however if you study that frame numbers page you will find that Australia seems to over represented with matching number bikes. It is believed that quite a number of Aust delivered bikes were left in storage and never put into service and sold off post war never needing an engine replaced and thus have matching numbers.

Ps. We all like seeing photos of peoples new bikes.

Re: introduction

Surplus bikes were auctioned off with a starting price of £ 10.00.00.
And in most cases that was also the hammer price because there were so many of them there was little competition between the bidders.
Large blocks were sold directly to the various BSA dealers for the same price AFAIK.
It was very common to replace military tin wear for civilian tin wear as a lot of used bikes were in some what less than pristine condition & the photos of them being transported to the sales sites shows that volume was more important than careful loading.
My bike was fitted with a 250 or 350 Empire Star tank & wheels which were obsolete stock by wars end .
A spot of black paint on the frame & no one would suspect it was a £ 10 army bike.
For the last 50 years Bill Green has been supplying WM20 owners with civilian tinwear but as significant anniversaries of WWII battles are coming arouns suddenly it has become very fashionable to return them to full "authentic" military trim including all the bike that never left their crates will well after VJ day.
Don't know where you are but the BSAOA SA is hosting this years BSA National Rally at Hahndorf this coming Fri -Sat & Sun if you can pop down there is generally 20 or so M20's there.

Does your bike have the original girder forks or has it had the telefork upgrade ?

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

Re: introduction

Hi Trevor,
As stated originally I am green to this bike and any upgrades. How can I identify what forks are on it ?

email (option): myf1@hotmail.com.au

Re: introduction

The type of forks shown in the current forum image ( and most of them ) are Girders.
Two rails down each side of the wheel and a big single spring.

Teles are modern forks, A single tube on each side of the wheel that telescopes.

Tele forked WM20's have a long front down tube that goes all the way down under the engine where it joins into the lower frame rails.
this is called the "long frame ".
The latter tele forked bikes had a shorter front tube that stopped at the front of the engine.

Because so many thousand WM20's were offloaded here there was a special offset triple trees made where the holes for the fork leg on the bottom clamp plate were a little forward of the ones in the top plate .
This pushed the front wheel a little more forward os it cleared the frame when compressed/
AFAIK these were only sold in Australia.
Weather they were a BSA product or made for a dealer to upgrade old war bikes I ave no idea.

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

Re: introduction

Thanks Trevor, learning all the time. It has a girder fork setup. I am disassembling the bike but I have no idea what nut head size the bike is, obviously not metric, I bought a set of AF and they are not right, Whitworth I believe is the thread size, can you help with the general type of spanner and socket that would cover the bike ?
Cheers

email (option): myf1@hotmail.com.au

Re: introduction

You need Whitworth/BSF spanners and sockets and the threads are mostly 26 tpi BSC (British Standard Cycle) with some BSF, Whitworth and 20tpi BSC thrown in. Ron

email (option): ronpier@talk21.com

Re: introduction

sacko
Thanks Trevor, learning all the time. It has a girder fork setup. I am disassembling the bike but I have no idea what nut head size the bike is, obviously not metric, I bought a set of AF and they are not right, Whitworth I believe is the thread size, can you help with the general type of spanner and socket that would cover the bike ?
Cheers
Car boot sales, church car park sales, and to a lesser extent swap meets are going to become a very popular place for you to visit.
This is because they are where you will find Whitworth tools at reasonable prices.
Amazon & ebay prices have become stupid, because they are the same tools needed to work on a $ 300,000 Brough .
These tools can be marked WW, BSW, or BS.
Now here is the confusing bit.The sizes are not the head size but the shaft size on the bolt.
And to get really confusing there was a reduction in actual size off the heads so many tool will have 2 numbers on each end, A WW & a BS

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

Re: introduction

Hi I have 40775 C4357367 here in NZ.
Not sure how it got here.
Cheers
John

email (option): jsaft1951@xtra.co.nz

Nieuwe pagina 1