The single spring clutch is also known as the "Empire Star" clutch, so presumably it was fitted to the start of that model in 1936. Ron
email (option): ronpier@talk21.com
When I bought this book I thought it could be for the prototype or 3 machines supplied to the government for trials in 1936-7. it certainly seems to be from that era and its still possible.
All 4 of these machines had "EX" frame numbers so they weren't just machines from that years production randomly selected for the trials, they were different or specially prepared?
Does anyone have access to the 1936-1937 BSA ledgers, how many HM20s and JM20s were made?
Rob
I don't think the "W" stands for War at this stage around 1935/6.
Although this new Val Page engine is quite different than the earlier W models think it is more likely it refers to these.
O&M states that the early testmodels suffered from "the old BSA curse of cylinder bore and piston wear", maybe the various changes in bore and strokes dimensions had something to do with this?
Rob, I can probably date is based on the C-number (C2171) at the bottom of the last page (before the WD). I have a comprehensive list of all BSA factory documentation that I have collected over the years and they all have C number which are sequential based on the dates that are referenced. Regards, Leon
email (option): leonhop3_at_planet_dot_nl
That would be great Leon.
Any thoughts about the "Drawing Office Copy" on the front?
Rob
Based on my list this booklet was printed in 1936.
email (option): leonhop3_planet_dot_nl
Regarding the 'Drawing Office copy'...When I worked in an engineering drawing office the originals of engineering drawings for parts and sub assemblies were kept on file...Also, the machine handbooks/manuals were produced by the drawing office...All the illustrations in those days (much as at BSA I'd have thought) were hand drawn in pencil and then Indian ink by an industrial artist...The end product was then copied and 'shrunk' or 'enlarged' as required...Again the originals of the drawings were on file along with a library of the finished books....
Your book found its way out of BSA and it's not beyond the realms of possibility it was either 'liberated' or recovered from the skips they filled up when the factory was emptied...I visited BSA just after the closure and there were parts and documents scattered about everywhere...I picked up a few nice freebies at the time!...
Someone I know has a manual recovered from the Triumph factory after the 1940 bombing and then issued...It has a rubber stamp on the front cover 'Damaged due to enemy action'....Ian
email (option): ian@wright52.plus.com
Thank you leon
Rob
Thanks Ian so its likely to be the BSA drawing office rather than the War Office or patent office.
I had heard of letters and parcels being marked damaged by enemy action by the GPO as an excuse for damage or lateness.
Am I right BSAs first year of M20 production was September 1936 to September 1937 and was the HM20?
Rob
Rob, Yes that is correct. That is when the first new models started rolling out of the factory.
email (option): leonhop3_at_planet_dot_nl
['I had heard of letters and parcels being marked damaged by enemy action by the GPO as an excuse for damage or lateness...']
They're still using that one...:laughing: :laughing:...Ian
email (option): ian@wright52.plus.com
The bike pictured is definitely 1937-38 from the style of oil tank and its mounting and the smooth timing cover. Fully agree with the 1936 date of the book showing the proposed 1937 model, the 1937 season starting at the end of August 1936.
The illustrations therefore show the proposed model which became the 1937 M20. The reference to Model W is curious but it makes sense in view of the fact that the M20 replaced the 500cc side valve W6 of the 1936 model lineup, that suggests that this book was produced before the 1937 M series models were called the M series models, with the new Val Page engines for the start of the 1937 season.
As the book was kept in-house at BSA it survived! Later editions would no doubt have been issued to the public with M rather than W on the cover.
At a glance, HM20 production about 1200 machines, JM20 production about 800.
Most interesting Rupert. We can thank the (now deleted) spammers for bringing this thread to the top and to your attention.
Maybe there is some purpose to their God-forsaken miserable existence after all ! :smile:
BSA Model designations continue to puzzle me. I'm glad that I'm a Noton man.
I seem to have spent a lifetime living in the past so being only a few months out of date in this case is quite good for me...
Rupert. Thank you for the production numbers for 1937/38. I have been looking for this information for some time. Most information I can find relates to WD years (understandable on this forum) and very little information is published about the parents of the WD models.
Lionel
Hi Lionel, happy to help where possible. I've done a more exact count if it might help:
HM20 (HM19 frame) 1253 produced.
JM20 (JM19 frame) 747 produced.
Anecdote - Val Page gets the bulk of the credit for these BSA engines introduced for the 1937 season, but the whole story of how these engines (and the whole bike) went from drawing board into production was very much a team effort. BSA's in-house team of design engineers (under direction from Val Page before he moved on) had the job of knocking the designs into shape for production.
At that time the top in-house design engineer - working directly under Val Page - at BSA was Herbert Perkins. I knew Herbert Perkins grandson (until he passed-on last year) who related a story passed down by his mum who was present at the following -
The AA bought a large number of the 1938 M20's for their patrolmen. Herbert Perkins out in his car with his family some time before WW2 came upon an AA patrolman with broken down M20 at the side of the road. He stopped and offered assistance to the patrolman and quickly got the bike up and running.
The amazed patrolman was more than curious; "What did you do? How did you know what to do?"
Reply from HP; "It's my engine".
Patrolman: "Who are you?" to HP as he walked away,
HP's shouted reply; "Perkins, BSA!"
Val Page is foremost of many brilliantly gifted engineers who worked in the British bike industry, a small number of whom tend(ed) to get all the headline publicity. Under those headlines was an awful lot of small print which is now largely lost.
Nice to know of the relatively low number of HM20's produced. I own one with the engine number HM20 176. Does this make it the 75th M20 ever made? Do many others survive?
email (option): fuzzyempire@hotmail.com
Rupert. My apologies for not responding to your updated numbers. I obviously missed that message. Many thanks for the interest.
Hamish, my engine number is 484 so I guess that makes it the 383rd engine produced. I hope others will respond on this as these models get very little recognition anywhere.