Troy-Bilt 645A Super Bronco Benutzerhandbuch

19

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 en-
gine 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 outermost 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 measure-
ment is between 1/6" -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) 

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 lo-
cated inside the spring clockwise (viewed 
from operator’s position) to increase ten-
sion on the spring. Turn the screw counter-
clockwise to decrease tension. Once 
adjusted, reattach the spring to the For-
ward Clutch Bail. 

e. Repeat Steps 2 and 3 to re-measure the 

length of the spring. When the second mea-
surement is between 1/16" -to- 3/16" longer 
than the first measurement, retighten the hex 
nut (C) against the top of the adjuster (B). 

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.

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.