Ryobi GD200A Operator's Manual page 18

ADJUSTING THE BELT TENSION
See Figures 18 - 21.
 Using a 1/2 in. socket, turn the tension nut clockwise
to tighten the belt and counter-clockwise to loosen it.
Adjust the nut until there is approximately 3/8 to 1/2 in.
of exposed thread showing above it or until the base of
the nut is aligned with the edge of the brace.
 When properly tensioned, there should be about a
1/8 in. gap between the belt and the edges of the rail near
the center of the rail assembly.
3/8 in. to
1/2 in.
Edge of
the brace
ASSEMBLY
Tighten
Loosen
Fig. 19
Base of
the nut
Fig. 20
ATTACHING RAIL ASSEMBLY TO POWER
HEAD
See Figures 22 - 25.
 Locate the following items:
Power Head
Bracket (2)
Nut (7/16 in.) [4]
Sprocket
Rail Assembly
 Place the power head on a towel or the packaging material
with the light cover facing down. Do not place the unit
directly on hard surfaces as this may damage the light
cover and motion sensor.
CENTER OF RAIL ASSEMBLY
Rail
Edge
Sprocket
18 - English
Round
Side
Shaft
1/8 in.
Gap
Belt
Fig. 21
Fig. 22