Rudge 1939 sport Special 500 cc 1 cyl ohv



Rudge   1939    “ Sports  Special”     500cc four-valve single    

The Rudge_Whitworth company was an established bicycle factory that entered motorcycle production in 1911. 
Their first machines were 499 cc IOE singles. They developed the famous Multi gear, with a possibility of up to 21 gear positions. 
In 1924 the factory introduced a new range of four valve singles. 
In 1928 Graham Walker managed to win the Ulster Grand Prix on a Rudge, after a heroic handlebar-to handlebar battle with Charlie Dodson on a Model 90 Sunbeam. 
Since then the sporty Rudge models were designated “Ulster”. 
In 1931 the engine was scaled down to 250 cc and that proved to be a real winner too, judging from 1st,  2nd and 4th places plus the lap record in the Junior TT. 
Rudge used several layouts for its 4 valve models and from the 1931 model range on they settled for the semi-radial arrangement of parallel inlets ( in a flat head surface) for deep breathing and radial exhausts ( in a part spherical surface) for cool running.  
At the same time plug size was reduced from 18 to 14 mm to allow more metal between the hole and the exhaust seats. 
This layout proved very successful and was retained till the end of Rudge production in 1940. 
An important new  feature for the 1937 range was the enclosure of the valve gear by a neat aluminium cover.  
The “Special” was  the touring version of the “Ulster “.  
From the 1937 model range  a more sporty “Special” was brought out in the form of the “ Sports Special” . 
This model had  almost identical specifications to those of the “Special”, but it sported high-level exhaust pipes and polished ports. 
This  high quality British post-vintage sports mount is an older restoration .