Technical Information · issue 25 of 2005
Connection between crankshaft and flywheel – degreased and oil-free
IssueTI 25/2005
Full text
Page 1 of 2
STIH)
Technical Information 25.2005
STIHL two-stroke and 4-MIX engines
Connection between crankshaft and
flywheel – degreased and oil-free
The connection between crankshaft and flywheel is The nut (1) pushes the flywheel (2) onto the
a frictional connection. Crankshaft and flywheel are crankshaft (3) and creates the necessary surface
pressed together so firmly that the flywheel is pressure to hold the flywheel securely on the
securely held on the crankshaft without twisting. crankshaft without twisting.
The mating surfaces must be free from oil and
grease in order to achieve such a connection.
The taper interference fit guarantees a precisely
centred fit.
The woodruff key (1) is used exclusively to position
the flywheel in relation to the crankshaft (correct
ignition timing).
TI_25_2005_30_01_01.fm englisch / English USA
)m~ge 2 Technical Information 25.2005
Fitting the flywheel
The crankshaft taper and hole of the flywheel hub
must be cleaned and degreased before being
installed!
Soiled, greasy or oily surfaces would cause the
flywheel to be excessively prestressed and the
permissible surface pressure would be exceeded.
This would result in cracks and damage to the
flywheel, causing it to fail.
2 3
000TI042 KN
. Clean the crankshaft taper (3) and hole (2) in
the flywheel hub with a standard solvent-based
degreasant not containing any chlorinated or
halogenated hydrocarbons.
. Examine the woodruff key or integrally moulded
key for signs of damage – replace the woodruff
key or flywheel if necessary.
. Ensure that the woodruff key (1)
is correctly seated – the key is moulded onto the
flywheel in some cases.
. Fit the flywheel and position it correctly – the key
must be lined up with the groove.
. Fit the locking nut or screw and tighten down
with the specified torque.
© ANDREAS STIHL AG & Co. KG, 2005 Technical Information
D1/MTK-bl
TI_25_2005_30_01_01.fm Page 2 of 2
Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.