Oregon Harvester Handbook page 93

Guide Bar Troubleshooting
14. Nose burned at tip from the
saw chain sliding on rails of the
sprocket nose guide bar, or from
the sprocket being recessed into
the tip.
Cause: High saw chain tension from
automatic saw chain tensioners .
Symptoms: Nose breakage from
bearings wearing quickly and jamming .
Remedy: Decrease the tension applied
by the automatic saw chain tensioner .
15. Loose or missing nose/
attachment rivets.
Cause: The guide bar tip flexing
during operation from difficult cutting
conditions or accidents .
Symptoms: Rivets continue to loosen
until laminates spread and the
bearings are lost .
Remedy: Check rivets every 100 machine
hours . Rehammer loose rivets and
replace rivets if the rivet head is missing .
Always use new rivets .
16. Burn ring around nose rivets.
Cause: Bearings overheated .
Symptoms: Premature breakage,
jamming, wearing of the sprocket
nose components .
Remedy: Check for proper oil flow
rates . Saw chips will plug oil line or
guide bar oil hole . Clean out the bar oil
hole daily . Install a wire mesh screen
on the oil tank filler spout to prevent
chips from getting into the tank .
17. Tabs on the replaceable nose
sprocket (RSN) break off.
Cause: Accidental bending of the nose .
Symptoms: RSN no longer functions .
Remedy: Install new RSN . Avoid
bending the RSN .
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Mechanical Timber Harvesting Handbook