Honda F506 Owner's Manual page 27

2.Handlebar height adjustment
The handle position should be adjusted to suit the stature of the
operator and work condition.
CAUTION:
Before adjusting the handlebar, place the tiller on the firm level ground
to prevent the handle from collapsing accidentally.
To adjust the handlebar height, loosen the adjuster, select the
appropriate position and tighten the adjuster.
HANDLE HEIGHT ADJUSTER
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