This is the set of primary drive gears for a wet clutch only.
Ratio is 54/84 as per original TR750's, this takes some of the load from the clutch and gearbox. Note this needs pressing into the standard crankshaft and riveting onto the standard clutch basket.
Reduces power loss from side thrust at the expense of noise.
Power increase from using straight-cut primaries can be as high as 15%