MacDon CA25 OM - Manual (Page 143)

SECTION 8. MAINTENANCE AND SERVICING
169593
141
Revision B
8.9.9.3 Sickle Drive Timing
Double Knife Harvest Headers 35 ft. and
smaller require that sickles are properly timed
to move in opposite directions.
To adjust sickle timing, proceed as follows:
a. Remove right sickle drive belt. Refer to
Removal: Right End Timing Belt on previous
page.
b. Rotate left sickle drive box driven pulley (A)
clockwise until left sickle (B) is at the center of
the inboard stoke (moving towards center of
header).
NOTE
Center stroke is when sickle sections
are centered between guard points as
shown.
c. Rotate right sickle drive box pulley (C)
counterclockwise until right sickle (D) is at the
center of the inboard stroke.
d. Install right sickle drive box drive belt, and
adjust tension. Refer to Installation: Right End
Timing Belt on previous page.
IMPORTANT
To maintain timing, sickle drive box
driver and driven pulleys must NOT
rotate as the belt is tightened.
e. Check that timing belts are properly seated in
grooves on both driver and driven pulleys.
f. Check for correct sickle timing by rotating the
drive slowly by hand, and observe sickles
where they overlap at center of the header.
IMPORTANT
Sickles must move in opposite
directions, and must begin moving
at exactly the same time.
If timing is off, proceed as follows:
1. Loosen right belt sufficiently to allow
skipping the belt one or more teeth as
required. Refer to Refer to 8.9.9.1. Left
End Drive, Tension Adjustment: Timing
Belt.
2. If right sickle leads left sickle, rotate RIGHT
SIDE driven pulley (C) clockwise.
3. If right sickle lags left sickle, rotate RIGHT
SIDE driven pulley (C) counterclockwise.
4. Tighten right belt.
RIGHT
SICKLE
LEFT
SICKLE
DIRECTION OF
MOVEMENT
SECTIONS CENTERED
BETWEEN GUARDS
B
D
A
C
RIGHT
SICKLE
LEFT
SICKLE
DIRECTION OF
MOVEMENT
SECTIONS CENTERED
BETWEEN GUARDS
B
D