Troy-Bilt 640C, 644A Checkingand Adjusting, Forwarddrive Belt Tension, Handlebarsee -4 and re

moving partsto come to a complete stop, disconnectspark plug wire and move wire awayfrom

,_ WARNING: Beforeinspecting, cleaning or servicing the machine,shut off engine, wait for all spark plug. Failureto follow these instructions can result in serious personal injury or property

damage.

b. Unthreadthe hex nut (C,Figure 5-4) halfway up the adjustment screw (D).

c. Unhookthe top of the spring from the

		Forward Clutch Bail.
		d. Usepliers to preventthe adjuster (B)
		from turning andturn the slotted screw lo-
		cated inside the spring clockwise (viewed
		from operator'sposition) to increaseten-
		sion onthe spring. Turn the screw counter-
		clockwise to decreasetension. Once
		adjusted, reattachthe spring to the For-
	C	ward Clutch Bail.
	\	e. RepeatSteps2and3to re-measurethe
		length of the spring. Whenthe secondmea-
		surementis between1/16"-to- 3/16" longer
		thanthefirst measurement,retightenthe hex
FORWARD		nut (C)againstthe top of the adjuster(B).
		ReplacementBelt Information
Figure 5-3: Instafl tinesso that cutting edge of tines enter soft first when tiller movesforward.		If the drive belt needsto be replaced,see
		your local authorizeddealeror refer to the
CHECKINGAND ADJUSTING	tension is correct if this second measure-	Parts List for ordering information. Use
FORWARDDRIVE BELT TENSION	ment is between1/6"-to- 3/16" longer than	only afactory-authorized belt as an "over-
	the first measurement.	the-counter" belt may not perform satis-
It is important to maintain correct tension	4. If the spring is too short (lessthan	factorily. The procedure requires average
on the forward drive belt. A loose belt will		mechanicalability andcommonly available
	1/16"), the tension is too loose. If the
causethe tinesandwheelsto slow down--
		tools.
	spring is too long (more than 3/16"), the
or stop completely -- eventhough the en-
	tension is too tight.
gine is running at full speed. A too tight
belt can result in unintentional tine move-	5. Toadjust the length of the spring:
ment when the clutch bail is in the Neutral	a. Releasethe Forward Clutch Bail.
(released) position.

• Checkbelt tension after the first two hours of break-in operation andafter every 10 operating hours.

• At the end of each tilling season, check the belt for cracks, cuts or frayededges and replace it as soon as possible.

To Check ForwardBelt Tension:

1.Stop engine, wait for all parts to stop moving and disconnect spark plug wire.

2.With the ForwardClutch Bailinan open (released) position, measureand note the overall length of the cable spring (A, Figure

5-4) by measuringfrom the outermost coil to the outermost coil.

3. SqueezetheForwardClutch Bailagainst	Figure5-4: Tocheckforwardbelt tension, take twomeasurementsof the
	overa// /ength of the coils in the spring--first with the dutch bail open,
the handlebar(see Figure 5-4) and re-
	then with the dutch bail closedagainst the handlebar.
measurethe length of the coils. The belt

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