Ok folks, let me do some maths to clear things up. I am using values from the specifications found in the official service manual.
Primary reduction ratio is 82/48 (1.708).
Gear ratio in 6th gear is 29/27 (1.074).
Secondary reduction ratio with standard sprockets is 48/15 (3.200).
Diameter of the rear wheel is around 600 mm (depending on tire type, pressure, rotation speed etc), so circumference at 100 km/h must be around 1900 mm.
Let's assume 5000 rpm.
5000 / 1.708 / 1.074 / 3.2 = 852 rpm = 51120 wheel rotations per hour
51120 rotations per hour * 1900 mm = 97 km/h
So we can roughly calculate 6th gear speed/rpm ratios with the following:
50 rpm -> 1 km/h
80 rpm -> 1 mph (5600 rpm -> 70 mph)
My Fazer's instruments confirm these numbers. Also gearingcommander.com gives almost the same results.
Primary reduction ratio is 82/48 (1.708).
Gear ratio in 6th gear is 29/27 (1.074).
Secondary reduction ratio with standard sprockets is 48/15 (3.200).
Diameter of the rear wheel is around 600 mm (depending on tire type, pressure, rotation speed etc), so circumference at 100 km/h must be around 1900 mm.
Let's assume 5000 rpm.
5000 / 1.708 / 1.074 / 3.2 = 852 rpm = 51120 wheel rotations per hour
51120 rotations per hour * 1900 mm = 97 km/h
So we can roughly calculate 6th gear speed/rpm ratios with the following:
50 rpm -> 1 km/h
80 rpm -> 1 mph (5600 rpm -> 70 mph)
My Fazer's instruments confirm these numbers. Also gearingcommander.com gives almost the same results.