1919 2 ¾ h.p. "Calthorpe-Jap"

1916 calthorpe jap
1920 jap

Appearance As 1916 Model (left) and 1920 Model (right)

Click here for detailed top view

Both types of JAP 2 ¾ h.p. engines seem to have been used in 1919 and the change would (we assume) have been forced on Calthorpe by JAP's redesign of the rear magneto engine. There was a realisation among many bike makers that magnetos were getting cooked behind the cylinder perhaps due to the arduous war conditions in which they had been used and as such there was a rush to put the magneto in a cooler (but much wetter) spot. These machines, which can be approximately dated by UK registration dates, show the forward magneto engine was available by the summer of 1919.



As 1916 or 1920 versions.




Additional Information - (Available to members in downloads section)

  • The Motor Cycle, May 22nd 1919 - The Levis Cup Report Article.
  • Calthorpe Letter, Dated 28th July 1919.