Hi Speedy and Norm,
Some of the flywheels have a centre steel insert with the taper so you wouldn't want to drill into that and weaken the taper support or
weaken the alloy taper on the alloy flywheel ,the measurement is where the factory drills the later alloy flywheel and as Norm said
going out further could break the flywheel ,the alloy centre flywheel comes off really easily with the puller with the 3 holes.
The other way to remove them is to put the nut flush with the end of the crank then hold two levers that are levering on the
flywheel and at the same time hit the flywheel nut with a hammer.The motor must be off the ground to do this and is not easily done
by one person but I've done it this way a few times.
The drilling method saves time for the next time the flywheel is removed.
Cheers
Max.
