Smiths NOS Racing Right Angle Motorcycle Drive 2 to 1 Bearing Type. This is a rare Smiths Tach drive. Full information on these drives can be found on the website The Velobanjogent under Smiths drives.
This is a new old stock GB1507/02
The following information was provided by the site and you will find additional information which should be helpful
o if your tacho is what we call a clockwise tacho and say 4-1 ratio, and your point of drive is a magneto and anticlockwise rotation, then you need to reverse the direction of the cable and give it another 2-1 reduction.
You need a 2-1 reversing tachometer drive gearbox.
From the charts on the following posted items, this would be a bronze 70549 2-1, a BG1508/01 or BG1508/06 or a BG1507/02…….
Stock number DRV BG1507/02