Engine Measurement; Measurement Procedures; Cylinder Head Warpage; Cylinder Taper - Rotax 2005 717 RFI Engine Shop Manual

MEASUREMENT PROCEDURES

NOTE: This section explains the procedures to
correctly measure engine components. For the
engine technical specifications, refer to INSPEC-
TION in the appropriate ENGINE subsection.

CYLINDER HEAD WARPAGE

Check gasketed surface of the cylinder head with
a straight edge and a feeler gauge. Make sure part
is within the given specification. If cylinder head is
out of specification, replace it. Verify combustion
chamber volume to use the correct cylinder base
gasket with the new part.

CYLINDER TAPER

Using a cylinder bore gauge, measure cylinder di-
ameter at 16 mm (5/8 in) from top of cylinder just
below auxiliary transfer port, facing exhaust port
and just below the auxiliary transfer port facing
the exhaust port. Compare readings. If the dif-
ference between readings exceed specification,
cylinder should be rebored and honed or replaced.
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F01D8AA
TYPICAL
1. Measuring perpendicularly (90°) to piston pin axis
2. Auxiliary transfer port
A. 16 mm (5/8 in)
smr2005-085
Section 01 ENGINE MEASUREMENT
Subsection 01 (MEASUREMENT PROCEDURES)

CYLINDER OUT OF ROUND

Using a cylinder bore gauge, measure cylinder
diameter at 16 mm (5/8 in) from top of cylinder.
Measure diameter in piston pin axis direction
then perpendicularly (90°) to it. If the difference
between readings exceed specification, cylinder
should be rebored and honed or replaced.
F01D8BA
TYPICAL
1. Measuring in piston pin axis
2. Measuring perpendicularly (90°) to piston pin axis
A. 16 mm (5/8 in)
COMBUSTION CHAMBER
VOLUME MEASUREMENT
NOTE: This procedure is required to determine
the thickness of the cylinder base gasket to be in-
stalled if a crank repair has involved replacement
of connecting rods or if you are experiencing
repetitive engine seizure.
The combustion chamber volume is the region in
the cylinder head above the piston at Top Dead
Center (TDC). It is measured with the cylinder
head installed on the engine.
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