Triumph 1920 Model H 550 cc 1 cyl sv



Triumph   1920    549 cc   Model H     frame #  310930  engine #  70925 HRX

The model H is announced late in 1914 as a logical development of the famous veteran        “ Trusty”. But it  isn’t just  a 1914 model with a countershaft gearbox: the engine differs from the veteran engine in various ways. 
It has a single cam wheel  with 2 cams instead of separate cam wheels for the inlet and exhaust valve. 
The casting for the cylinder is entirely new, the valve head diameter is enlarged by  ¼ inch and the valves are spaced further apart. 
A great improvement over the 1914 style 3-speed hub is the Sturmey Archer countershaft gearbox. 
The primary chain drive is enclosed by a neat aluminium cover; secondary drive is by belt.
The new model  becomes available  in  February 1915 and most of the production goes to the British Armed forces; in 1918 the army has just over 17,000 Model H’s. 
It is not until 1919 that the  Model H is again available, in very small numbers, for the civilian market and many ex- army machines are sold off at surplus sales at Slough.  
A large number of  machines are overhauled by the factory  for resale in 1919 through 1921. For the 1920 model year the frame is strengthened and sidecar lugs are added. 
The big end bearing is improved by the use of a double set of rollers and the upper rear engine-to-frame crankcase mounting is made stronger by the addition of a rib. 
At the same time the external valve gear is redesigned. From 15 till the end of production in 1924 some 45,000 Model “H” machines are manufactured.
(source: Peter Cornelius) For detailed information on  the Model “H”  consult Peter Cornelius’  “The Facts” booklet,   surf to
The engine code  HRX refers to July 1920 as assembly month. 
This practical vintage machine has been restored  some 30 years ago and has seen little use since. 
She  is  a good runner  and comes complete with   acetylene lighting set, bulb horn and a pair of tool boxes.