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Technical Information · issue 13 of 1997

021, 023 L: Crank drive (crankshaft; piston; conne

Model STIHL 021, 023, 025 Chainsaws - Series 1123

IssueTI 13/1997
Engine family 1123
From serial 34 191 135, 34 944 403

Part changes (1)

WasBecomesWhat the bulletin says
1123 031 0500 1123 030 0409 The original one-piece crankshaft 1123 031 0500 was replaced by the new multi-part crankshaft 1123 030 0409 from machine number X 34 944 403.

Full text

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TI 13/1997 page 1
Technical Information

                                                                                                 13.97

Model STIHL 021, 023, 025 Chainsaws  -  Series 1123

&RQWHQWV

1. 021: Crank drive (crankshaft, piston, connecting rod, cylindrical rollers)

2. 023 L: AV system (softer annular buffers)
3. 025: California only: Carburetor (WT 283 A replaces WT 313)

1.=021: Crank drive 

1.1=Crankshaft 

The original one-piece crankshaft 1123 031 0500
was replaced by the new multi-part crankshaft
1123 030 0409 from machine number
X 34 944 403.
Features of new crankshaft:
• Composite design pressed together to form a

   torsonally rigid unit.
• The small-end needle sleeve is press-fitted in
   the connecting rod.

                                                                                                         135TI034 KN
   In the case of replacement crankshafts for

   models 023 and 025, the needle cage is
   installed along with the piston pin.
                                                           Left:     Original crankshaft 1123 031 0500
                                                           Right:    New crankshaft 1123 030 0409

1.2=Piston

Piston 1123 030 2003 must be used with the
new crankshaft 1123 030 0409.
The original piston 1123 030 2001 remains availa-

ble for machines with the old crankshaft 1123 031
0500.

Service note=========================================================================================~
The original piston 1123 030 2001 must still be
installed in model 023 saws.
                                                                                                         135TI035 KN

The difference between these pistons is the
dimension D:                                               D = 12.7 mm: Original piston 1123 030 2001
                                                           D = 12.2 mm: New piston 1123 030 2003
)Technical Information 13.97  -  Page 2

1.3=Connecting rod, cylindrical rollers

The connecting rod and the new crankshaft are an
inseparable part.

For this reason the connecting rod 1123 030 1202
and set of cylindrical rollers 1123 007 1005 will no
longer be used on the production line, but they will
remain available as spare parts.

1.4 Summary

Item      Part Name                                    Original               New             Rem.
                                                       version                version

  1       Crankshaft                                   1123 031 0500          1123 030 0409   1)
  2       Connecting rod                               1123 030 1202          ---             1)
  3       Set of cylindrical rollers                               fo
                                                       1123 007 1005          ---             1)

  4       Cylinder with piston;                        1123 020 1215          1123 020 1218   1)
          including item 5

  5       Piston Ø 40 mm                               1123 030 2001          1123 030 2003   1) 2)

  6       Cylinder with piston (California);           1123 020 1210          1123 020 1219   1)
          including item 5

Modification to be introduced from machine
number X 34 944 403

5HPDUNV

1) Original version of part remains available for older machines

2) Original piston 1123 030 2001 must still be installed in model 023 saws.
)Technical Information 13.97  -  Page 3

2.=023 L: AV system 

The AV system has been made softer in order to
further enhance user comfort.

The annular buffers have been changed - see sum-
mary.
                                                                                       3
The numbers in the illustration on the right corre-
                                                                                 2
spond to the item numbers in the summary below.

                                                                                                  135TI036 KN
                                                                           1           2

6XPPDU\

Item      Part Name                                   Original         New                 Rem.
                                                      version          version

  1
  2
          Annular buffer
          Annular buffer
                                                      1127 790 9900
                                                      1123 790 9900
                                                                       1123 790 9901
                                                                       1123 790 9901
                                                                                           1)
                                                                                           1)
  3       Annular buffer                              1123 791 2805    1123 791 2806       1)

Modification to be introduced: in progress

5HPDUNV

1) Original version of part remains available as spare
)Technical Information 13.97  -  Page 4

3.=025: Carburetor =California only

For the 025 saws from machine number
X 34 191 135=the original WT 313 carburetor will
be replaced by carburetor WT 283 A, which is
already installed in models 021 and 023.

The spare parts for both carburetors are, with the
exception of the fixed jets, identical.
Fixed jet 1123 121 5615 (Ø 0.6 mm), installed in
the WT 313, has been deleted.

Fixed jet 1123 121 5610 may be installed as a

replacement in WT 313.

6XPPDU\

Item      Part Name                                  Original           New             Rem.
                                                     version            version

  1       Carburetor WT 313;                         1123 120 0612      ---             1)
          including item 3

  2       Carburetor WT 283 A                        ---
                                                                   fo   1123 120 0610   2)
  3       Fixed jet Ø 0.6 mm                         1123 121 5615      ---             1)

Modification to be introduced from machine
number X 34 191 135

5HPDUNV

1) Original version of part no longer available from factory
2) Already a spare part for models 021 and 023

Last Technical Information on models 021, 023, 025: TI 38.96

 1997 Andreas Stihl                   Andreas Stihl - D1/MTK-st
                                       Technical Documentation                               5973

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