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Technical Information · issue 17 of 2001

New Model FR 85 T Backpack Brushcutter

Model FR tool Sound Sound Vibration Vibration

IssueTI 17/2001

Full text

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TI 17/2001 page 1
Technical Information

                                                                                           17.2001
New Model FR 85 T Backpack Brushcutter – Series 4137

Contents
1.   Technical Description
2.   Specifications

3.   Tools

4.   Accessories
5.   Service Accessories
6.   Repairs

7.   Spare Parts

The new FR 85 T (T = split boom) backpack             The following Multi-Cut attachments are currently
brushcutter extends the line of units for landscape   available: BC, FC, FH, HL (0°, 30° and 0 ... 90°)
maintenance.                                          and HT.
The quick-action coupling on the shaft enables a      The engine (series 4137 powerhead) and the
number of different attachments from the STIHL        ergonomically designed controls are exactly the
Multi-Cut system to be used to broaden the range of   same as those of the STIHL FR 85.
possible applications and make transportation more
convenient.                                           Recommended applications are the same as those
                                                      for the respective STIHL single-purpose power
The quick-action coupling is designed in such a way   tools.
that the shafts engage without having to be turned
back and forth.

TI_17_2001_01_01_01.fm                                                                 englisch / english
)m~ge 2                                                                       Technical Information 17.2001

1.     Technical Description
Engine, gearhead, controls and handle system are
the same as those of the STIHL FR 85.

Split boom / drive shafts
.     Quickly disassembled to save space for
      transportation
.     Rigid shafts

                                                                                                                393TI005 KN
2.     Specifications

2.1    Powerhead

2.1.1 Engine
Single cylinder two-stroke engine
Displacement:             25.4 cm3
Bore:                     34 mm
Stroke:                   28 mm
Engine power to           0.95 kW (1.3 hp)

ISO 8893:                 at 8,500 rpm
Engine speeds:            see 2.1.2
Rewind starter:           Single pawl system
Starter rope:             3 mm dia., 800 mm long

Clutch: engages at:       3,700 rpm

Model       FR tool              Sound            Sound            Vibration               Vibration
            or                   pressure level   power level      measurement             measurement

            Multi-Cut            Lpeq             Lweq             to ISO 7916             to ISO 7916
            attachment           to               to               Idle speed              Max. RPM

                                 ISO 7917 1)      ISO 108841)      (m/s2)                  (m/s2)
                                                                   Handle                  Handle
                                 dB (A)           dB (A)           right       left        right       left

FR 85 T Cutting head             92               106              0.8         0.5         2.7         2.4
FR 85 T Metal tool               89               103              0.6         0.5         3.3         1.8

FR 85 T Multi-Cut                88 ... 96        103 ... 107      0.5 ... 0.8 0.4 ... 1.6 2.6 ... 6.6 1.8 ... 4.1
        attachment
1) Weighted equivalent level includes idling and racing with the same duration of exposure

2.1.2 Fuel System
Carburetor: All position diaphragm carburetor with integral fuel pump
Idle speed screw LD (standard setting)                            Open 2 full turns (see 6.1)
Idle speed                                                        2,500 to 3,100 rpm
Cutoff speed range (electronic speed governor)                    9,700 to 11,300 rpm

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Technical Information 17.2001                                                                      Page 3

Fuel tank capacity:        0.44 L (440 cm3)
Fuel mix:                  Regular grade gasoline (leaded or unleaded) and two-stroke engine oil
Mix ratio:                 50:1 with STIHL 50:1 two-stroke engine oil
                           25:1 with other brand-name two-stroke engine oils

2.1.3 Ignition System

Ignition module:         with integral electronic speed
                         governor

Spark plug                Bosch WSR 6F,

(suppressed):             NGK BPMR 7 A or
                          Champion RCJ 6Y

2.2   Weight

without cutting tool and deflector
FR 85 T:                                    9.6 kg
3.    Tools

3.1   FR Cutting Tools

                                                                      1                  2
The following cutting tools are approved
1     STIHL SuperCut 20-2            4002 710 2162

2     STIHL AutoCut 21-2             4002 710 2113

3     STIHL AutoCut 25-2             4002 710 2108                3                      4

4     STIHL TrimCut 30-2             4002 710 2122

5     STIHL PolyCut 20-3             4002 710 2130                          5
6     Cutting blade 230-2*           4001 713 3805

7     Cutting blade 230-4*           4001 713 3801
8     Cutting blade 230-8*           4001 713 3803
9     Brush knife 250-3*             4112 713 4100

                                                                  6                  7
*     Not approved for
      loop handle FR 85 T
      without barrier bar

                                                              8                      9
                                                                                                       265TI004 KN

TI_17_2001_01_01_01.fm
)m~ge 4                                                           Technical Information 17.2001

3.2    Multi-Cut Attachments
Basic unit:
1 FR 85 T (shown without FS attachment)

2     BC cultivator                           * Note:
3     FC edger                                No other power tool attachments may be mounted
4     FH power scythe                         to the short stub shaft (approx. 42 cm) of the HL 0°
5     HL 0° hedge trimmer*                    hedge trimmer attachment.
6     HL 30° hedge trimmer
7     HL 0 ... 90° hedge trimmer
8     HT pole pruner

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Technical Information 17.2001                                                                       Page 5

4.    Accessories

4.1   General

Part Name                         Part No.              Application
ElastoStart                       0000 190 3400         Rewind starter (grip with rope)

Starter rope                      0000 195 8200         Rewind starter

STIHL gear lubricant for hedge                          Drive shafts in tube, flexible shaft
trimmers

- 80 g tube                       0781 120 1109

- 225 g tube                      0781 120 1110

STIHL gear lubricant for                                Gearhead

brushcutters
- 80 g tube                       0781 120 1117

- 225 g tube                      0781 120 1118

STIHL special oil                                       Rewind spring in starter,
- 100 ml bottle                   0781 417 1315
                                                        bearing bore in rope rotor
4.2   Nylon Line for Cutting Heads

Line diameter / Color        Application
2.4 mm / orange              SuperCut 20-2, AutoCut 21-2, AutoCut 25-2, TrimCut 30-2, PolyCut 20-3
2.7 mm / red                 PolyCut 20-3

5.    Service Accessories

5.1   Special Servicing Tools

Special servicing tools are listed in the service manuals for STIHL FS 75, 80, 85, FC 75, HL 75 (powerhead,
controls, gearhead), STIHL FR 350, 450 (support frame) and the appropriate STIHL single-purpose power tools
for the Multi-Cut attachments.

5.2   Servicing Aids

Part Name                          Part No.              Application

Carburetor parts kit               4227 007 1060         Zama
Grease                             0781 120 1111         Oil seals
- 225 g tube
Dirko sealant                      0783 830 2120         Engine pan/cylinder sealing faces
Set of screws                      5910 007 1060         Replacement screws and nuts
Electrician’s repair kit           5910 007 1050         Electrical system
Standard commercial solvent-                             Cleaning crankshaft stub
based degreasant containing no
chlorinated or hydrogenated
hydrocarbons

TI_17_2001_01_01_01.fm
)m~ge 6                                                                       Technical Information 17.2001

6.      Repairs
If the unit is started up in the course of repairs, it is essential to strictly observe all country-specific
safety regulations and the safety precautions outlined in the owner’s manual.

6.1     Replacing and lubricating the shafts

6.1.1 Lower part of drive tube
.     Loosen the wing screw (1), pull the lower part of
      the drive tube (2) out of the coupling sleeve (3).                         3                       2
.     Remove the gearhead/attachment from the

      drive tube.


                                                                                                                 393TI008 KN
.     Press down the lock button and hold it there, pull
      the drive shaft (4) with sleeve (5) out of the drive
      tube (applying pressure to other end of the shaft
      simplifies this operation).
If the shaft has turned blue, install a new one.

.     Coat the drive shaft with STIHL gear lubricant                                        5 4
      for hedge trimmers, never pump grease into the
      drive tube.

                                                                                                               393TI009 KN
.     Push drive shaft (4) and sleeve (5) into the drive

      tube.
.     Press down the lock button and push the sleeve
      (5) home as far as stop (lock button must snap

      into position).
.     Fit and line up the gearhead/attachment.

6.1.2 Upper part of drive tube
.     Loosen the clamp screw (6) and pull the

      coupling sleeve (7) off the drive tube. Press
      down the lock button and hold it there, pull the
      drive shaft (8) with sleeve (9) out of the drive
      tube.                                                                 6          7
If the shaft has turned blue, install a new one.
.     Coat the drive shaft with STIHL gear lubricant
                                                                                                                393TI010 KN

      for hedge trimmers, never pump grease into the
      drive tube.
                                                                                 9   8

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Technical Information 17.2001                                                Page 7

.     Push the drive shaft (8) and sleeve (9) into the
      drive tube. Press down the lock button and push
      the sleeve (9) home as far as stop (lock button
      must snap into position) - it may be necessary to
      turn the shaft back and forth in this process.
                                                                     9   8
.     Push the coupling sleeve (7) on to the drive tube
      as far as stop – the lug must engage the slot –
      and line up so that the gap in the clamp and the
      machine support face downwards.

                                                                                 393TI011 KN
.

      Tighten down the clamp screw (6) firmly.

.     Refit the lower part of the drive tube with the
                                                                 6       7
      gearhead/attachment.

6.2     Tightening Torques

Tightening torques are listed in the service manuals
for STIHL FS 75, 80, 85, FC 75, HL 75 (powerhead,
controls, gearhead), STIHL FR 350, 450 (support
frame) and the manuals of the appropriate STIHL
single-purpose power tools for the Multi-Cut
attachments.

6.3     Service Note
Refer to the following service manuals for servicing

and repair procedures: STIHL FS 75, 80, 85, FC 75,
HL 75 (powerhead, controls, gearhead), STIHL FR

350, 450 (support frame) and the manuals of the
appropriate STIHL single-purpose power tools for
the Multi-Cut attachments

These service manuals do not include the chapters
"Servicing the Carburetor", "Troubleshooting" or any

repairs involving standard procedures. Such
procedures are described in separate handbooks,
i.e. “Carburetors” and "Standard Repairs,

Troubleshooting".

TI_17_2001_01_01_01.fm
)m~ge 8                                                                        Technical Information 17.2001

6.4   Repair Times                                        .
The specified repair times assume that the work is                Repair procedure                   FR 85 T
performed by trained personnel in a properly                  1   Remove and refit engine              20
equipped service workshop.
                                                              2   Crankcase, pressure test*           110
The repair times are given in minutes.                        3   Crankshaft, bearings,               110
Note: This table for the FR 85 T can be added to the              pressure test*
STIHL repair times table.                                     4   Sealing rings, pressure test*         70
                                                              5   Crankcase leakage test, test run      40
                                                              6   Cylinder, piston, pressure test*      55
                                                              7   Ignition system, contact*             10

                                                              8   Fuel supply, tank vent,               10

7.    Spare Parts
                                                                  test run
The spare parts for the FR 85 T and the Multi-Cut             9   Manifold or flange,                    -
attachments are included in the illustrated parts lists           pressure test

for the equivalent single-purpose units.                  10      Carburetor, check*                    30
                                                          11      Handle and throttle control           10

                                                          12      Rewind starter, test run              15
                                                          13      Clutch, test run                      20
                                                          14
                                                          15
                                                                  Muffler
                                                                  Air filter
                                                                                                        10
                                                                                                         5
                                                          16      Stop switch, test run                 10
                                                          17      Clutch housing                        20
                                                          18      Drive tube                            25

                                                          19      Replace gearhead or bearing            5
                                                                  housing
                                                          20      Limit stop or deflector               10

                                                          21      Drive shaft                           15

                                                          22      Fuel tank                             20
                                                          23      Check compression pressure             -
                                                          24      Adjust valve clearance                 -

                                                          25      Replace crankcase,                     -
                                                                  bottom half
                                                          26      Replace crankshaft                     -

                                                          27      Replace cylinder, piston               -
                                                          28      Oil supply                             -
                                                          29      Oil pump, test run                     -

                                                                                               ✂

                                                          * Test run under load

© 2000 Andreas Stihl AG & Co.                             Technical Documentation
  Waiblingen                                              D1/MTK-na                                          7175

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