Sorry fact with Riley 9hp timing…..there are 13 teeth on the crank gear…so that equates to 27.7 deg. of crank revolution per tooth….which makes it that you can, at worse, be up to 13.8 deg. out at cam.
That is a long way out…..if you have just spent a fortune on New cams to then run them when not spot on is foolish.
Brooklands Enginecraft adjustable gears give the the opportunity to set the cams spot on and the whole set up takes no more than 5 minutes…..
Another problem with Magneto engines is that the mag can be between teeth for optimum spark timing…….have had to re-cut key ways here before now…BTH to dissy conversion solves this one.