Yamaha YFM660FS Owner's Manual page 179

Spark plug:
Type/manufacturer
Spark plug gap
Clutch type:
Transmission:
Primary reduction system
Secondary reduction system
Secondary reduction ratio
Transmission type
Operation
Reverse gear
Sub transmission ratio
Chassis:
Frame type
Caster angle
Trail
Tire:
Type
Size
Model
low
high
front
rear
DPR8EA-9 / NGK
0.8–0.9 mm (0.031–0.035 in)
Wet, centrifugal automatic
V-belt
Shaft drive
41/21 × 24/18 × 33/9 (9.544)
V-belt automatic
Left hand operation
25/17 (1.471)
35/17 (2.058)
26/21 (1.238)
Steel tube frame
5°
26 mm (1.02 in)
Tubeless
×
AT25 8 - 12
×
AT25 10 - 12
10-4
YFM660F