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Technical Information · issue 38 of 2002

Gear mechanism; Sprocket cover; Oil tank; HT safety harness (not for HTE 60); Angle gear (special accessory); Service note HT 75; Summary

IssueTI 38/2002

Part changes (2)

WasBecomesWhat the bulletin says
4138 640 0114 4138 640 0120 4138 640 0114 have been replaced by the new versions 4138 640 0120 and 4138 640 0116.
4138 640 1700 4138 640 1701 The sprocket cover 4138 640 1700 has been replaced by the new version 4138 640 1701.

Full text

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TI 38/2002 page 1
Technical Information

                                                                                                      38.2002
STIHL HT 70, HT 75, HT, HT-KM Pole Pruners – Series 4138
STIHL HT 73 Pole Pruner – Series 4142

Contents
1.   Gear mechanism

2.   Sprocket cover
3.   Oil tank
4.   HT harness
5.   Service note HT 73, HT 75

6.   Summary

1.    Gear mechanism                                             The new sprocket cover includes an additional

The two gear mechanisms 4138 640 0111 and
                                                                 opening at the top for better discharge of the wood
                                                                 chips.
4138 640 0114 have been replaced by the new
versions 4138 640 0120 and 4138 640 0116.
The transmission ratio of the gear mechanisms has
been changed from 0.8 to 1.2. This yields a lower

chain speed and higher torque.
A new sprocket with six teeth is now available. This
further increases the torque at the chain.

The existing sprocket with seven teeth will remain

available as a spare part.

                                                                                                                    386TI006 KN
2.    Sprocket cover

                                                                 Left: previous sprocket cover

                                                                 Right: new sprocket cover

                                                                 The chain catcher pin is now integrated into the

                                                                 cover. Its position has been changed by 1.6 in
                                                                 (40 mm). This enlarges the opening at the bottom
                                                                 and improves chip discharge.

                                                   386TI000 KN

Left: previous sprocket cover
Right: new sprocket cover

The sprocket cover 4138 640 1700 has been
replaced by the new version 4138 640 1701.

TI_38_2002_02_01_01.fm                                                                                english / USA
)m~ge 2                                                                            Technical Information 38.2002

3.    Oil tank                                                 4.   HT harness

                                                 386TI002 KN

Left: previous oil tank
Right: new oil tank

The oil tank 4138 351 0300 is new and re-designed.

The new oil tank has a new filler cap.
The tank capacity has been increased by
approx. 70 %.

                                                                                                                  386TI004 KN
The wall strength has been improved. The new oil
tank is sealed against the gear housing by the
gasket 4138 351 1000. The oil tank is screwed onto
the gearbox at four points.

                                                               The new HT harness 4138 710 9000 is now
Service note:                                                  available so that the pole pruner can be carried
The four screws on the oil tank must be tightened              more comfortably.
crosswise during assembly. Tightening torque 6 Nm              It includes a sling to support the power unit of the

(50 in-lbs).                                                   pole pruner. This permits an ergonomic working

The new oil tank requires a new strainer                       position. The sling is supported on the operator's
1117 647 6801 and connector 4138 353 2700. The                 thigh.
strainer 1117 647 6801 has a larger surface and                The thigh strap and carrying strap can be adjusted
                                                               as required.

therefore a longer interval between cleanings.

                                                               5.   Service note HT 73, HT 75

                                                               When mounting the shaft on the HT 73 and HT 75,
                                                               care must be taken to ensure that the snap ring
                                                               9458 621 1130 (arrow) is correctly inserted in the

                                                               groove of the drive shaft.

                                                 386TI008 KN

Strainer 1117 647 6801 (right) mounted in the
connector 4138 353 2700
                                                                                                                  386TI005 KN

                                                                                              TI_38_2002_02_01_01.fm

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TI 38/2002 page 2
Technical Information 38.2002                                                                  Page 3

6.     Summary
Item     Part name                               Previous             New                 Remarks
         HT 70, HT, HT-KM only:
 1       Gear mechanism, including Item 3        4138 640 0111        4138 640 0120       1)
 2       Sprocket 3/8" Picco, 7 teeth            1206 642 1301        ---                 1)
 3       Sprocket 3/8" Picco, 6 teeth            ---                  4138 642 1201
         HT 73, HT 75 only:
 4       Gear mechanism, including Item 6        4138 640 0114        4138 640 0116       1)
 5       Sprocket 3/8" Picco, 7 teeth            4138 642 1350        ---                 1)

 6       Sprocket 3/8" Picco, 6 teeth            ---                  4138 642 1250

         All versions
 7       Oil tank                                4138 350 4400        4138 351 0300       1)
 8       Oil filler cap                          1206 640 3600        0000 350 0526       1)

 9       Gasket                                  ---                  4138 351 1000
10       Sprocket cover                          4138 640 1700        4138 640 1701       1)

11       Strainer                                4138 351 9300        1117 647 6801       1)
12       Rubber buffer                           4138 353 2900                            1)
13
14
         Connector
         Valve
                                                 ---
                                                 ---
                                                          fo          4138 353 2700
                                                                      1128 640 9100
15       Full harness HT,                        ---                  4138 710 9000
         including Items 16, 17
16       Full harness                            ---                  4134 710 9004

17       Sling                                   ---                  4138 790 2800
Modification to be introduced: continuously
Remarks

1) Previous version of part remains available for older machines

Last Technical Information on models STIHL HT 70, HT 73, HT 75, HT, HT-KM: 16.2001, 32.2001

© 2002 Andreas Stihl AG & Co.                           Technical Documentation
  Waiblingen                                            D1/MTK-ja                               7670

TI_38_2002_02_01_01.fm

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TI 38/2002 page 3

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