Oregon Chain Saw Maintenance & Safety Manual page 68

GUIDE-BAR TROUBLESHOOTING (CONTINUED)
REMEDIES: (T-Y)
T. Shallow grooves and wire edges are the result of normal wear over
time. Use a flat file to square up the bar's rails and remove wire
edges promptly. Left alone, wire edges can break off, chipping
away good rail material, (pictures 31 and 32)
U. A thin or low rail is caused by one of two things: (1) crooked-cutting
chain, see pages 46, or (2) chain leaning over in a worn groove,
see picture 23, page 44. Replace the bar. Replace the chain as
well if chain continues to lean in the new bar. (picture 33)
V. Accidents or irregular operating techniques which push the drive
links sideways or place excessive pressure on the side of the nose
can cause breaks or cracks in the rails of solid-nose bars. Your
dealer may be able to repair minor damage on a relatively new
bar.
(pictures 34 and 35)
W. Pinched rails, lack of lubrication, or accidents and cutting
techniques which push the drive links sideways in the groove can
create extreme friction which causes blue discoloration.
spots on rails are soft and will wear rapidly. Replace the bar.
(picture 36, page 62)
X. Such wear or chipping near the nose often accompanies heavy
limbing, but can also be caused by loose chain tension. Invert the
bar on the saw periodically to reduce such wear. On replaceable-
nose bars with minor wear, install a new nose and file down the
nose's rails as shown on pages 53 and 54 for smooth chain flow. If
wear is extensive (on solid-nose or replaceable-nose bars), replace
the bar. (picture 37, previous page)
Y. Frequent boring cuts, loose chain tension, and accidents or irregular
operating techniques which twist the nose or push the drive links
sideways against the nose's rails will cause such breakage. Install
a new replaceable-sprocket nose if possible, otherwise replace the
bar. (pictures 38 and 39, previous page)
64.
64.
64.
Guide Bars Guide Bars
Blue