680ES OPERATOR MANUAL
42
© 2015 ICS®, Blount International Inc. Specifications are subject to
change without notice. REV071315 F/N 577451
Maintenance
DRIVE SPROCKET
• The drive sprocket (rim sprocket) is a wear item and
should be replaced every two to three chains, or
when the teeth become pointed or if groove cuts
through top of tooth.
• Inspect the sprocket for wear.
• The needle bearing inside the splined adapter
should be greased regularly and should be replaced
with each new clutch cup. A rim sprocket system
consists of a clutch cup w/ splined adapter and a rim
sprocket. When the rim sprocket wears out, it is the only part that needs to
be replaced. The clutch cup with splined adapter is a wear item that needs
replacement after 3 to 5 rim sprockets have been used.
• Check the drive sprocket bearing by spinning clutch cup. Replace the
bearing if it is worn out.
DRIVE SPROCKET ASSEMBLY REMOVAL/INSTALLATION
• Remove the side cover, guidebar, diamond chain, and clutch slurry shield.
• Remove the spark plug and insert the piston stop (supplied with each saw)
into the spark plug hole.
Pull the starter cord slowly until the piston stops. Use a 19 mm wrench to turn
the clutch
clockwise
and remove.
• Slide the clutch cup/drive sprocket assembly off the
shaft. Remove the needle bearing and inspect for
heavy wear or damage.
• Slide the rim sprocket onto the splined adapter,
either side out.
• Apply a liberal amount of grease to the needle
bearing.
• Place the thin metal washer onto drive shaft. Slide the needle bearing and
clutch cup w/rim sprocket onto shaft.
• Install the clutch by turning it
counter clockwise
on the drive shaft and
firmly tighten. Replace the clutch slurry shield. Installation of drive sprocket
assembly is now complete.
Clutch
Cup
Splined
Adapter
Rim
Sprocket