To advance the ex cam, should turn 1 tooth clockwise when looking at the timing marks from the l/h side of the bike. This works well on the 790 America/SM, with boost in torque in the low and mid range. This reduces overlap from 24 deg to 9 degrees.
Will not work on the 865 Speedmaster because their is no overlap, in fact both valves are closed for 7 degrees of crank rotation at TDC!! A side benefit of overlap is that cool intake charge flowing over an open exhaust valve assist in cooling the exhaust valve as well as scavenging the cylinder of exhaust gases.
Cheers...........Agro
