Tuning Machine Tension Adjustment - Yamaha Electric Bass Owner's Manual

The tuning machines have spring-loaded mechanisms which
automatically take up wear, preventing backlash. However, it is
possible to adjust the amount of pressure required to turn the
machines. Each machine has a tension adjustment screw, as
illustrated.
Loosen
Tighten

TUNING MACHINE TENSION ADJUSTMENT

Loosen
3
Clockwise rotation tightens the machine. The tuning machines
should be adjusted to the extent that they are firm, but can turn
smoothly. This adjustment is normally unnecessary, and exces-
sive tightening can lead to premature tuning machine wear.
Loosen
Tighten
Tighten