Hi Kerry
The Machine Register only lists your frame number as a 2.3/4 hp sidevalve. You say what you have is a "bitsa". The parts you have may give some clue as the model. if not then you have a choice of model to which to rebuild it as there are no existing factory records of the original build standard of machines leaving the factory for pre-war models.
To my knowledge there were three models available in 1918 namely Models U, V and W. . The model U had a two speed gearbox and footboards. Model V virtually identical with footpegs front and rear instead of footboards. Model W was the top of the range with a three speed gearbox and clutch. All were belt drive and usually available with a choice of high or low handlebars. There were two distinct build standards prevalent however, as the new version with round tube forks, a larger diameter steering head frame and larger fuel tank was introduced in 1916 but the older lightweight oval tube forks with their smaller diameter steering head frame and the narrower smaller fuel tank continued in production in parallel until about 1919.
Regards Chris.
