Here’s an oldie , but a goody.
3HP Model 140 Royal Enfield two speed. Its the 5th edition of this manual.
It includes Royal Enfields Patent Cush Drive and Patent Two-Speed and Free Engine Gear mechanism.
Its in PDF format so make sure you have Adobe Acrobat Reader
Click on the picture to open it in your browser or right-click and ‘Save as’ to download it