Technical Information · issue 38 of 2005

Tightening Torques; Rake Drive; Gearhead; Clutch (SP 81 and Basic Power Tools with Series 4137 Engine)

IssueTI 38/2005

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STIH)

Technical Information 38.2005

Servicing STIHL SP and STIHL SP 81 Special Harvesters – Series 4231

Contents
1. Tightening Torques
2. Rake Drive
2.1 Rake Drive / Forkhead
2.2 Chain Connector
2.3 Rakes
2.4 Forkhead
3. Gearhead
3.1 Disassembling the Gearhead
3.2 Assembling the Gearhead
4. Clutch (SP 81 and Basic Power Tools with Series 4137 Engine)
4.1 Clutch Shoe Retainers

1. Tightening Torques

Location Fastener Size Torque
[Nm]
Gearhead cover/gear housing Screw M4X12 3
Gear housing/pivot pin Nut M5 3
Gear housing/drive tube Screw DG5X24 9
Gearhead screw plug Hex head screw M11X10 9.5

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2. Rake Drive
Overview of components

. Remove the spring clip (1) and strap (2).
2.1 Rake Drive / Forkhead
A “rake kit” for repairing the rake drive is available
under part number 4231 740 7251. This kit contains
2 rakes, 2 chain connectors and 1 forkhead.
This kit should be used to replace all parts of the
rake drive even if only one side is worn.

2.2 Chain Connector

2.2.1 Removing the Chain Connector

. Pull out the chain connector (3).

2.2.2 Lubricating the Chain Connector
STIHL SP bearing grease 0781 120 1006 must be
used for lubricating the chain connectors.
. Clean the pins of the chain connector and the
bearing bores.

. Use a suitable tool to pry the spring clip (1) off
the chain connector.

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Technical Information 38.2005 Page 3

. Squeeze the tube of grease to obtain a small 2.3.2 Mounting the Rakes
quantity of grease. Observe the tightening torques in chapter 1.
. Coat each chain connector pin with SP bearing . Install the rakes in the reverse sequence.
grease.

2.4 Forkhead
2.2.3 Installing the Chain Connector
. Install and assemble the chain connector in the 2.4.1 Removing the Forkhead
reverse sequence. . Remove the rakes, see 2.2.1.

2.3 Rakes
1
2.3.1 Removing the Rakes
. Remove the chain connectors, see 2.1.1.

. Take out the 6 gearhead cover screws (1).

. Loosen the rake and unscrew one of the two
nuts (1, 2).

. Apply two screwdrivers to the notches (arrows)
to pry off and remove the gearhead cover (2)
together with the gasket.

. Pull out the pivot pin (3) and remove the
rake (4).

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2.4.2 Installing the Forkhead
Observe the tightening torques in chapter 1.
. Install the forkhead in the reverse sequence.

3. Gearhead

3.1 Disassembling the Gearhead
. Remove the gearhead from the drive tube.
. Use suitable circlip pliers to remove the internal . Remove the forkhead, see 2.3.1.
circlip (3) from the forkhead (4).

. Back off the set screw (1) on the underside of
the gearhead so that it is clear of the pinion
The pin has an M4 female thread. bearing.
. Fit a screw (5) in the thread (e.g. gearhead
cover screw) and use it to pull out the pin (6).

. Press the drive pinion (with bearings) out of its
seat.
. Pull the forkhead (4) out of the gearhead.

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Technical Information 38.2005 Page 5

. Remove the circlip (2). . Take the needle bearing (5) out of the
connecting rod (6).

. Use a standard puller to remove the bearings (3) . Remove the connecting rod (6).
from the drive pinion.

. Use a suitable tool to pry the crown wheel (4) out . Remove the thrust plate (7).
of the housing.

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. Use a hot air blower to heat the gear housing (8) . Carefully press home the drive pinion until it
until the bearing drops out. runs without play, then secure it with the set
screw on the underside of the housing.
. Now reverse the disassembly procedure to
3.2 Assembling the Gearhead assemble all other parts.
Observe the specified tightening torques (see
chapter 1).
. Press the bearing into the gear housing.
. Reverse the disassembly procedure to re- 4. Clutch (SP 81 and Basic Power
assemble the gearhead as far as the drive Tools with Series 4137 Engine)
pinion.
4.1 Clutch Shoe Retainers
The latest retainers (1127 162 3000) must be used
for repairs to the clutch. The shape of these
retainers differs from that of those installed in
previous versions of models FS 75, 80, 85, FR 85,
HS 75, 80, HT 70, 75, SP 85 etc., see TI 42.2004.

. Use a standard puller to install the bearings on
the drive pinion and secure them with the circlip.

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