This Link    launches a RPM to road speed calculator. (Assuming Top Gear is1:1)

This Link   launches a Piston Drop to Crank Rotation calculator. This is useful because Norton quotes piston drop in inches - no help if you fit a timing disc and want to strobe. The maths here is not as simple as you think and I am grateful to my son John who supplied the formula.

This Link   launches a calculator to work out cubic capacity from Bore, Stroke and amount of overbore. Not complicated, but I was asked recently for this.