Valigrunt Performance

Putting the Muscle back into Classic Cars

Strengthening the Gearbox and Clutch

December 23, 2024

As often happens when you make more torque in a motor the other components of a driveline need to be strengthened to cope with the extra force being run through them.  The Harley was no exception to this rule and it was quickly realised that the original clutch and gearbox were not coping with the extra power being made by the motor.  The first thing noticed was that the power being made by the stroked motor was not making it to the ground, allot of this was being absorbed by the clutch and gear box slipping.  After riding his Sportster for a while the fourth gear in the box broke and 3rd gear was damaged, so the gears were upgraded and a heavy duty clutch was installed and this in turn allowed more of the power to make it to the ground and the Harley to go faster again.