Ski-Doo Formula S 1998, Shop Manual

Page: 105 / 338

Section 04 ENGINE
Subsection 04 (LEAK TEST AND ENGINE DIMENSION MEASUREMENT)
04-04-8
Read the measurement on the cylinder bore
gauge. The result is the exact piston/cylinder wall
clearance. If clearance exceeds specified toler-
ance, replace cylinder or rebore. Refer to TECHNI-
CAL DATA 10.
NOTE: Make sure the cylinder bore gauge indica-
tor is set exactly at the same position as with the
micrometer, otherwise the reading will be false.
RING/PISTON GROOVE
CLEARANCE
Using a feeler gauge check clearance between
ring and groove. Replace piston if clearance ex-
ceeds specified tolerance. Refer to TECHNICAL
DATA 10.
RING END GAP
Position ring half way between transfer ports and
intake port. On rotary valve engines, position ring
just below transfer ports.
NOTE: In order to correctly position the ring in the
cylinder, use piston as a pusher.
Using a feeler gauge, check ring end gap. Replace
ring. If gap exceeds specified tolerance, refer to
TECHNICAL DATA 10.
1. Transfer port
2. Intake port
CRANKSHAFT DEFLECTION
Crankshaft deflection is measured with a dial indi-
cator.
Measuring (in engine)
First, check deflection with crankshaft in engine.
If deflection exceeds the specified tolerance, re-
check deflection using V-shaped blocks to deter-
mine the defective part(s). See below.
Measuring (on bench)
Once engine is disassembled, check crankshaft
deflection on V-shaped blocks. If deflection ex-
ceeds the specified tolerance, it can be worn
bearings or a bent crankshaft. Remove crankshaft
bearings and check deflection again on V-shaped
blocks to determine the defective part(s). See
measurement A in following illustration.
TYPICAL
1. Measure at mid point between the key and the first thread
A. See table below
A01C0PA
A01C0QA
2
1
A
A01C0RA
1