Troy-Bilt 634B-Super Bronco - Manual (Page 19)

Section 5: Maintenance 19
Before inspecting, cleaning or servicing the machine, shut off engine, wait for all moving parts to
come to a complete stop, disconnect spark plug wire and move wire away from spark plug.
Failure to follow these instructions can result in serious personal injury or property damage.
WARNING
CHECKING AND ADJUSTING
FORWARD DRIVE BELT TENSION
It is important to maintain correct tension
on the forward drive belt. A loose belt will
cause the tines and wheels to slow down –
or stop completely – even though the
engine is running at full speed. A too tight
belt can result in unintentional tine move-
ment when the clutch bail is in the Neutral
(released) position.
• Check belt tension after the first two
hours of break-in operation and after
every 10 operating hours.
• At the end of each tilling season, check
the belt for cracks, cuts or frayed edges
and replace it as soon as possible.
To Check Forward Belt Tension:
1. Stop engine, wait for all parts to stop
moving and disconnect spark plug wire.
2. With the Forward Clutch Bail in an
open (released) position, measure and
note the overall length of the cable spring
(A, Figure 5-4) by measuring from the out-
ermost coil to the outermost coil.
3. Squeeze the Forward Clutch Bail
against the handlebar (see Figure 5-4) and
re-measure the length of the coils. The
belt tension is correct if this second
measurement is between 1/16" -to- 3/16"
longer than the first measurement.
4. If the spring is too short (less than
1/16"), the tension is too loose. If the
spring is too long (more than 3/16"), the
tension is too tight.
5. To adjust the length of the spring:
a. Release the Forward Clutch Bail.
b. Unthread the hex nut (C, Figure 5-4)
about halfway up the adjustment
screw (D).
c. Unhook the top of the spring from
the Forward Clutch Bail.
d. Use pliers to prevent the adjuster (B)
from turning and turn the slotted
screw located inside the spring
clockwise (viewed from operator’s
position) to increase tension on the
spring. Turn the screw counter-
clockwise to decrease tension. Once
adjusted, reattach the spring to the
Forward Clutch Bail.
e. Repeat Steps 2 and 3 to re-measure
the length of the spring. When the
second measurement is between
1/16" -to- 3/16" longer than the first
measurement, retighten the hex nut
(C) against the top of the adjuster (B).
Replacement Belt Information
If the drive belt needs to be replaced, see
your local authorized dealer or refer to the
Parts List for ordering information. Use
only a factory-authorized belt as an “over-
the-counter” belt may not perform satis-
factorily. The procedure requires average
mechanical ability and commonly available
tools.
Figure 5-3: Install tines so that cutting edge of tines enter soil first when tiller moves forward.
A
D
C
B
E
ENGINE
Figure 5-4: To check forward belt tension, take two measurements of
the overall length of the coils in the spring – first with the clutch bail
open, then with the clutch bail closed against the handlebar.
1
2
3
4
5
B
D
C
A
Hold bail against handlebar while
taking second measurement of
spring