Stihl 021 Specifications

Stihl 021 Chainsaw Specifications

Stihl 021 Specifications for Stihl 21 chainsaw, Find the specs and detailed information for the Stihl chainsaw including engine, fuel ignition system and cutting attachments.

Stihl 021 Specifications

021 Chainsaw Engine: STIHL single-cylinder two-stroke engine with special impregnated cylinder bore.

Displacement: 35.2 cm3 (2.15
Bore: 40 mm, (1.57 in)
Stroke: 28 mm, 32 mm (1.10 in)
Power output to ISO 7293: 1.5 kW (2.0 bhp) at 9,000 rpm
Max. permissible engine speed (with bar and chain): 11,500 rpm
Idle speed: 2,800 rpm
Bearings: Crankshaft supported in heavy-duty ball bearings, needle cages on small and big ends, Cylindrical rollers on big end
Piston pin diameter: 10 mm (0.39 in)
Rewind starter: Pawl engagement
Pawls: Single pawl system
Reserve pull on rope rotor: min. 1/2 turn
Starter rope: 3.0 mm (0.12 in) diameter
Clutch engages at: 3,600 rpm
Crankcase leakage test:
at gauge pressure: 0.5 bar (7.25 psi)
under vacuum: 0.5 bar (7.25 psi)

Stihl 021 Specifications Fuel System

Carburetor: Diaphragm carburetor
Standard setting on carburetors with three adjusting screws
High speed screw H: Open approx. 1 turn
Low speed screw L: Open approx. 1 turn
Carburetor leakage test at gauge pressure: 0.8 bar (11.6 psi)
Function of tank vent at gauge pressure: (±) 0.3 bar (4.35 psi)
under vacuum: (±) 0.05 bar (0.725 psi)
Fuel tank capacity: 0.47 l (1 US pt)
Octane rating: min. 90 RON (US/CAN; pump octane min. 87)
Fuel mixture: Regular brand name gasoline and two-stroke engine oil
Mix ratio: 50:1 with STIHL two-stroke engine oil, 25:1 with other brand name two-stroke, air-cooled engine oils
Air filter:Box filter, fabric or fleece filter

Stihl 021 Specifications Ignition System

Type: Electronic magneto ignition (breakerless) with integral trigger unit
Air gap: 0.2 – 0.4 mm (0.008 – 0.016 in)
Spark plug (suppressed): Bosch WSR 6F, NGK BPMR 7 A, Champion RCJ 6Y or Autolite 298
Electrode gap: 0.5 mm (0.020 in)

Cutting Attachments

Chain lubrication: Fully automatic speed-controlled oil pump with rotary piston
Oil deivery rate: approx. 7.5 cm3/min (0.25 fl.oz/min) at 10,000 rpm
Oil tank capacity: 0.20 l (0.4 US pt)

Special accessories
For User

STIHL repair kit 1123 900 5000
3/8″ P, 8-tooth rim sprocket kit 1123 007 1001
.325″, 7-tooth rim sprocket kit 1123 007 1003
.325″, 8-tooth rim sprocket kit 1123 007 1002
1/4″, 8-tooth spur sprocket 1123 640 2010
3/8″ P, 7-tooth spur sprocket 1123 640 2000
.325″, 7-tooth spur sprocket 1123 640 2015
.325″, 8-tooth spur sprocket 1123 640 2020
Side chain tensioner kit 1123 007 1000

For Service Carburetor parts kit 1123 007 1061

Stihl 021 Specifications Tightening Torques

DG screws are used in the polymer and light-alloy components. These screws form a permanent thread
when they are installed for the first time. They can be removed and installed as often as necessary without
detrimentally affecting the strength of the screwed assembly, providing the specified tightening torque is
observed. For this reason it is essential to use a torque wrench when making adjustments from the Stihl 021 Specifications.


More Stihl 021 Specifications information can be found in Carburetor Manuals HERE and a Stihl 021 chainsaw workshop manual HERE. Stihl Parts list HERE a chainsaw search (magnifier icon) at top and bottom of this page, as well as a chainsaw repair help question and answer page HERE.

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