BSA 1938 M22 500cc 1 cyl ohv



BSA   1938   496 cc   OHV    SPORTS  M 22      frame # JM 19 2321  engine #  JM 22299

Responsible for the 1937 range of BSA machines was brilliant engineer Val Page.
He reshaped the complicated system of machine types that had become confusingly diverse over the years. 
The 150 cc machine was dropped and all 250 cc and 350 cc models were catalogued  in the “B” group, while all the other singles  above 350cc came into the “M” group.
The V-twins formed the third group. So now the whole range was divided into only three groups.
That is to say, the  750 cc  v-twin was labeled the Y 13 and the 1000cc twin the G 14 and to make sure it would not become too transparent for the customers there was one  350 cc model that fell in the “M” group, the   350 cc OHV De Luxe M 19. 
Page replaced the forged backbone frame system with a fully brazed-up frame with one top tube. 
The crankcase sump was
discontinued, the magdyno became rearward-mounted again and  the valve gear enclosure was improved in such a way that for the first time there was a complete coverage for the whole of the overhead gear. 
The cylinders were air-hardened to reduce wear.
There were 3 models in the 500 cc ohv class that all had a four speed foot controlled gearbox: the M22 OHV Sports, the M 23 Empire Star and the M 24 Gold Star.
All three had  had bore/stroke dimensions of 82×94 mm.  
This M22 is equipped with the optional two port cylinder head and high level exhausts, which could be ordered for 65 Pounds extra. 
Over three years time, only 300 model M22 twin ports were made,  which makes it a very rare model.
The machine has been restored and is a good runner.