Troy-Bilt 12087 - Manual (Page 52)

REVERSE DRIVE MAINTENANCE
A
WARNING
To help avoid personal injury,
stop the engine, wait for all
moving parts to come to a
complete stop, remove the
electric start key, disconnect
the spark plug wire and move
the wire away from the plug,
and let the engine and muf­
fler cool before inspecting,
adjusting or replacing the re­
verse drive components.
These instructions explain how
to inspect, replace or adjust the
various reverse drive components.
But first, here’s how the reverse
drive system works: When you
raise the Wheels/Tines/PTO Drive
Lever up in REVERSE position,
this lowers the rubberized reverse
disc (it’s attached to the engine
drive pulley) until this rotating disc
contacts the transmission drive
pulley. The friction between the
rotating reverse disc and the trans­
mission pulley causes the transmis­
sion drive shaft to be powered in a
counterclockwise direction (as
viewed from the operator’s posi­
tion behind handlebars). The drive
shaft then turns the wheels and tine
shafts in a reverse direction.
A. Reverse Disc Inspection
The reverse disc is made of steel
with a special, long-lasting rubber
compound bonded to the disc rim.
Since this is a wearing part, it
should be inspected after every 30
operating hours.
1. Measure the width of the out­
side edge of the disc as shown in
Photo 5-22. Replace the disc be­
fore the rubber edge wears to a
thickness of 1/8" or less. Failure to
do so could cause the steel under­
neath the rubber to damage the
transmission pulley.
2. Look for big cracks or missing
chunks of robber from the disc. If
so damaged, the disc should be re­
placed immediately.
IMPORTANT - Extend the life
of the reverse disc by always
pausing in NEUTRAL before
shifting between FORWARD
and REVERSE. Also - the re­
verse disc is not suited for con­
tinuous or sustained reverse op­
eration. Use reverse sparingly.
Photo 5-22: Measure the edge of
the reverse disc for wear.
B. Replacing the Reverse Disc
Follow these steps to replace the
reverse disc. (If your tiller has a
Bumper Attachment mounted, it
must be removed first.)
To Remove the Reverse Disc:
1. Move Wheels/Tines/PTO Drive
Lever in NEUTRAL position.
2. Wedge a 5/16"-thick board be­
tween the top of the engine pulley
(avoid contacting the reverse disc)
and the cast iron housing next to it.
This “freezes” the pulley.
3. Use a 9/16" wrench to loosen
the mounting bolt shown in Figure
5-23. Remember to freeze the pul­
ley with the wood wedge while
loosening the bolt. If necessary,
separate the disc from the pulley
with the tip of a screwdriver. Back
the bolt out as far as possible.
Then angle the disc a little to re­
move it. Bring the bolt and lock-
washer along with the disc. To Install a New Reverse Disc:
Just reverse steps l-through-3
described previously. Tighten the
mounting bolt securely, and check
for correct operation — see next
page for checking instructions.
Figure 5-23: Immobilize the pulley with a wood wedge, then loosen the bolt
so you can remove the rubber reverse disc. (The disc may need to be pried
away from the pulley.)
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