Technical Information · issue 17 of 1995

023 L: New low-noise version

Model 023 Chain Saws - Series 1123

IssueTI 17/1995

Engine family 1123

Full text

Page 1 of 10

Technical Information

17.95

Model 023 Chain Saws - Series 1123

New version: STIHL 023 L =low noise

1.=General description

The 023 L is the world’s quietest gasoline chain The following comparisons illustrate to what extent it
saw. has been possible to reduce the noise level on the
023 L:

Its from a low sound pressure level of only • Twelve 023 L saws running next to one
92 dB(A), measured at the operator’s ear, and its another at the same time produce the same
sound pattern enable it to be used in noise- amount of noise as one standard 023 saw.
sensitive areas:
• residential areas,
• public facilities (in the vicinity of hospitals,
nursing homes, parks, zoos, etc.)
)Technical Information 17.95 - Page 2

• An 023 L operating at a distance of 10 meters
(33 ft) is as loud as standing next to someone
using an electric typewriter.

The equivalent sound pressure level is calculated
from the individual sound pressure levels measured
at "idling speed", "cutting (full load)" and "racing
(no load)". The individual values are determined
according to ISO 7182.

2.=======Technical description

The low noise pressure level has been achieved
by modifications to the air intake, engine, muffler
and the new Picco Mini cutting attachment.

2.1.=====Engine

Ignition timing has been designed for high torque at
lower engine speeds. Maximum engine power is
produced at a relatively low rpm. fo
A new rubber element 1123 028 1400 is fitted
between the cylinder cooling fins at the clutch side.
This helps dampen noise produced by the cylinder

fins.

135TI008

The cover 1123 791 7505, fitted in the handle
housing, reduces sound waves radiating from the
engine.

135TI009
)Technical Information 17.95 - Page 3

2.2.===Intake side

A resonator has been incorporated at the intake
side. A resonator is a vibrating system which
damps frequencies in a certain range.

2.3.===Carburetor box cover / resonator

The space between the air inlet in the carburetor
box cover and the cylinder is totally encapsulated.
The individual components are sealed off from
each other. This has resulted in a filter box with

a defined volume.

Two channels are incorporated in the redesigned
carburetor box cover 1123 140 1905.

The length of the channels and the volume of the
filter box determine the frequencies which are to

be attenuated.

In the 023 L the filter box and the length of the
channels have been tuned so that high-frequency
sounds are filtered out, i.e. especially those
frequencies which are unpleasant to the human
ear.

135TI010

2.3.1.=New filter base with intake pipe

An intake pipe is integrally molded on the filter
base immediately in front of the carburetor. This

intake pipe improves volumetric efficiency and thus
ensures a higher torque.

Service note
The filter base has to be removed before

unscrewing the spark plug.

135TI012
)Technical Information 17.95 - Page 4

2.3.2.=Air filter

The air filter is fitted in the 023 L’s carburetor box
cover. It is pulled out for cleaning.

135TI013
2.4.===Muffler

The muffler features an integrated exhaust pipe
and thus functions as a resonator. This helps
reduce irritating high frequencies at the exhaust
side.
The wall thickness of the muffler has been
modified to optimize the sound pattern.

135TI014

2.5.===Hand guard

The hand guard (1) has been acoustically
decoupled from the machine by installing a rubber

bushing (2), i.e. the transmission of engine
vibrations to the hand guard has been greatly
reduced.

1 2

135TI015
)Technical Information 17.95 - Page 5

2.6.=====Throttle rod

The throttle rod in the 023 L has been adapted to
suit the filter system and now has part number
1123 182 1505. It can be installed in all series
1123 chain saws. For this reason the original
throttle rod 1123 182 1500 is no longer available
from the factory.

b
a

135TI016
Left: Original throttle rod,
a Z=OQ=mm (0.94")

Right: New version 1123 182 1505,
E = 38 mm (1.5")

2.7.=====Picco Mini cutting attachment=================fo
The new Picco Mini cutting attachment has been An 023 L with Picco Mini achieves the relatively
specially designed for small chain saws with good cutting performance of an 021 equipped with
engines up to 1.2 kW (1.6 BHP). Compared to a conventional Picco Micro.

the well-known Picco Micro, it offers:
The Picco Mini can be used together with the quick
• Higher cutting capacity chain tensioning system.
• 30% less weight

Picco Mini cutting attachments must not be used
• Reduced cutting noise
on machines with an engine power of more than
•

Less sensitive to variations in feed 1.2 kW (1.6 bhp).
pressure. This is a particular advantage
for inexperienced users

2.7.1.=3/8" Picco Micro Mini Oilomatic chain

The narrow Picco Micro Mini chain (PMN, N = The cutters of the PMN are marked "PN".
narrow) was developed on the basis of the time-

proven Picco-Micro (PM). The drive link is stamped with a "1" to denote the
drive link gauge for guide bars with a groove width
All components have been rated for a power range of 1.1 mm (0.043").
up to 1.2 kW (1.6 BHP).
A depth gauge setting of 0.45 mm (0.018") is
The higher cutting capacity of the PMN is primarily used for smooth-running characteristics.
the result of the 16% narrower kerf: less wood is
removed and therefore means that less lugging The offset depth gauge contributes to excellent
power is required to pull the chain along the bar. cutting performance.
)Technical Information 17.95 - Page 6

PM cutter PMN cutter

Comparison of PM with PMN

30 301

Chain pitch 3/8" P 3/8" P
Drive link gauge
Depth gauge setting
1.3 mm (0.050")
0.65 mm (0.025")
1.1 mm (0.043")
0.45 mm (0.018")
Width of kerf 6.4 mm (0.25") 5.4 mm (0.21")
Cutting performance 100 % 108 %

The rivet heads are concave on the PMN.
Concave riveting reduces friction in the cut and
generates less vibration.

Another advantage of concave rivet heads is that

they make it easier to center the chain breaking
punch for chain repairs.

135TI017

Left: Conventional convex=rivet
Right: New FRQFDYH rivet

Chain replacement parts

Right-hand cutter 3987 662 0400
Left-hand cutter 3987 662 0600
Preset tie strap 3987 660 6600
Tie strap without rivet 3987 662 1200
Green-label tie strap, for USA 3987 662 1203
Drive link 3987 662 1000
)Technical Information 17.95 - Page 7

2.7.2.=New filing gauge, sharpening
instructions, repair

The sharpening angles for the PMN are the same
as those of the PM. The only difference is the
depth gauge setting. It is 0.45 mm (0.018") on the
PMN.
A filing gauge modified for this depth gauge setting
is available under part number 0000 893 4000.
The setting data for PM chain should be used on
the USG. The clamping rails for chain with a drive
link gauge of 1.3 mm (0.050") are also used for the
PMN.

The same dies and punches can be used for
repairs to the PMN (e.g. with NG4 or NG5) as for
the standard PM chain. A few convex rivet heads

do not interfere with the chain’s smooth running
characteristics.

2.7.3.=New Rollomatic Mini guide bar

Made in Germany

The Rollomatic Mini is only 3.2 mm (0.126") thick, Rollomatic Mini guide bar, 3/8" P 7 T,

i.e. 0.7 mm (0.03") thinner than the standard bar. 30 cm (12") 3005 000 4105
It is the world’s first guide bar with a groove width
of only 1.1 mm (0.043"). The 7-tooth nose sprocket Rollomatic Mini guide bar, 3/8" P 7 T,
is secured to the blade with a single central rivet 35 cm (14") 3005 000 4109

and is not replaceable.

2.8.===Carburetor

The WT-360 carburetor with a fixed jet and part No provision is made for adjustment of maximum
load jet has been developed from the original engine speed. On these machines it is only
WT-215 carburetor. possible to correct the idling speed within fine
The new carburetor has no high speed screw (H limits.
screw). It guarantees an optimum fuel-air mixture With this carburetor the 023 L complies with the
and thus helps reduce exhaust emissions. Californian emission limits.
The maximum engine speed specified for
machines with a conventional carburetor does
not apply to this version.
)Technical Information 17.95 - Page 8

Low speed and idle speed screws are adjusted as
before (standard setting of L = 1, see owner’s
manual).

The following parts were modified:

2.8.1.===Fixed jet

The fixed jet in the new carburetor replaces the H
screw and adds the exact amount of fuel required
during full-load operation. Maximum engine speed 1
is permanently set by the fixed jet and cannot be

adjusted. The fixed jet is screwed into the bottom

of the metering chamber and can be easily
removed for cleaning.

2
1 = Part-load jet
2 = Fixed jet

2.8.2.=Part load jet

The part load jet injects a defined quantity of fuel
into the air flowing through the carburetor when the

throttle shutter is opened.
The part load jet is press-fitted in the carburetor

body and cannot be removed. It can be cleaned
with compressed air.

2.8.3.=Low speed screw

An 0-ring (1) and washer (2) are installed to
achieve an effective seal between the low speed
screw and carburetor body. This helps eliminate
the ingress of air through the screw thread.

1
2

135TI004
)Technical Information 17.95 - Page

2.9.===Grommet

The grommet used for carburetors without an
H screw has only two openings for the L and LA
screws. The new grommet is colored gray for easy
identification.

35TI005
Left: Original grommet

Right: Grommet for 023 L

2.10.=Annular buffer

Annular buffer 1127 790 9900 is installed in the
023 L in place of the original annular buffer
1123 790 9900 at the lower hand guard/engine
housing mounting point (arrow).

135TI018

3.=====Specifications

The following table only lists the specifications
which differ from those quoted in TI 03.90.

023 L=============023===============021

Power 1.1 kW (1.47 bhp) 1.9 kW (2.55 bhp) 1.5 kW (2.0 bhp)
Weight 4.7 kg (10.4 lb) 4.6 kg (10.1 lb) 4.5 kg (9.9 lb)

Cutting attachment see chapter 2.7
of this TI --- ---
Sound pressure level measured

at operator’s ear during cutting 92 dB(A) 103 dB(A) 100 dB(A)

Equivalent sound pressure level
measured at operator’s ear 89 dB(A) 102 dB(A) 99 dB(A)

4.=====Service note

If the saw is started up in the course of repairs or
maintenance work, it is essential to strictly observe
all local and national safety regulations and the
safety precautions outlined in the owner’s manual.
)Technical Information 17.95 - Page 10

5.=====New spare parts

Item Part Name Part No. Rem.

Cylinder with piston 1123 020 1213
Rubber element 1123 028 1400
Carburetor WT-360; 1123 120 0611
including items 1, 2, 3 and 4:
1 Fixed jet 0,48 1123 121 5630
2 Washer 1123 122 1500
3 Sealing ring 1123 122 3600

4 Low speed screw 1123 122 6802

Grommet 1123 123 7502
Carburetor box cover 1123 140 1905

Twist lock 1124 140 9500 2)
Air filter 1123 120 1601
Filter base 1123 120 3400
including item 5:

5 Slotted nut 1123 141 8310

Muffler USA, CAN, AUS;
including items 7 and 8:
1123 140 0607

7 Cover plate 1123 145 0607
8 Screen 1123 141 9001

Nameplate 023 L 1123 967 1506

Rubber bushing (on hand guard) 1123 792 5505
Chain sprocket cover 1123 640 1705 2)
Throttle rod 1123 182 1505 3)
Cover 1123 791 7505

Annular buffer 1127 790 9900 1)

5HPDUNV

1) Part is already available for other models
2) Replaces original chain sprocket cover 1123 648 0400 on all series 1123 saws
3) Replaces original throttle rod 1123 182 1500 on all series 1123 saws

Last Technical Informationen on models 021, 023, 025: TI 42.95

(California only: TI 41.94, 52.94)

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