G'day Dan. To save counting, there are 20T on the crankshaft cog and 82 on the clutch, then 10, of course, on the countershaft sprocket and ??? at the rear, (44T?).
The best way to calibrate your speedo, (although it sounds like it's good now), is to put the valve at the bottom and mark the spot on the floor, then, with your weight distributed on the bike as it would be when riding, roll forward one turn and measure the distance and enter that figure into your speedo as 'circumference'. If your speedo needs 'diameter', or for accurate calcs in the Gear Ratio Calculator, divide the circumference measurement by pi.
(Under load, my 26" front wheel is actually 25.57".)
As an aside, for anyone with a shift kit, you can still use this calculator for four ratios by combining the first two and entering them as the first ratio in GearRatio.exe.
ie. 20T to 82T = 4.1:1 and with standard countershaft and shift kit 10T to 17T the ratio is 1.7:1. Multiply 4.1 x 1.7 and enter that as the first ratio - 6.97:1. (1 tooth to 6.97 teeth)