Ignition timing on 1949 ES2

John- Main-Smith reprint of the Norton workshop manual for my 1950 ES 2 gives the ignition timing in piston travel and calls for 5/8 " BTDC with the mag set on full advance. I have ( with my daughter's help as she is the math wizard ! ) worked out the math solution via trigonometry to convert this to degrees of rotation. Given a 79 mm stroke ( 39.5 mm crankshaft throw) and a 7'' connecting rod length this equates to 41.622 degrees BTDC. I checked this by measuring the piston travel with a dial indicator and degree wheel/pointer set up and it was spot on- I do not know if these figures apply to your 1949 engine & I hope I haven't confused you further .Perhaps another member will know if the timing specs for 1949 are the same as for 1950 - Hope this helps-Richard

What does it work out at for a 100mm stroke? Regards John.

iv just done my es2 motor i just put piston tdc

then have the valves rocking each side of tdc slight overlap runs spot on

fast rev good starting

John (both Francis & Whiting !)- My apologies and I am feeling very foolish! The figures I gave you were indeed based upon a 100 mm stroke and in my reply I quoted the bore- that would have been a short stroke engine indeed ! Again, these are for ignition on full advance. Interestingly I have tried to gauge points opening with both the slip of paper method and by continuity across the points with a multimeter and the result was the same either way so the paper method is fine with me. Sorry for any more confusion from over here in the colonies- Richard