Testing Engine Compression - Arctic Cat WILDCAT/X Service Manual

1. Remove the spark plugs and timing inspection plug;
then remove the tappet covers (for more detailed
information, see Engine/Transmission - Servicing
Top-Side Components).
 NOTE: Remove the crankshaft end cap and install the
special cap screw (left-hand threads) to rotate the engine.
2. Rotate the crankshaft to the TDC position on the com-
pression stroke of the front cylinder. The stamped "F"
must be visible.
 NOTE: At this point, the rocker arms and adjuster
screws must not have pressure on them.
Feeler Gauge Procedure
A. Using a feeler gauge, check each valve/tappet clear-
ance. If clearance is not within specifications, loosen
the jam nut and rotate the tappet adjuster screw until
the clearance is within specifications. Tighten each
jam nut securely after completing the adjustment.
CAUTION
The feeler gauge must be positioned at the same angle
as the valve and valve adjuster for an accurate measure-
ment of clearance. Failure to measure the valve clear-
ance accurately could cause valve component damage.
VALVE/TAPPET CLEARANCE
Intake 0.1016 mm (0.004 in.)
Exhaust 0.1524 mm (0.006 in.)
B. Rotate the engine 270° to the TDC position of the rear
cylinder; then repeat step A. The stamped "R" must be
visible.
8
Valve Adjuster Procedure
A. Place the Valve Clearance Adjuster onto the jam
nut securing the tappet adjuster screw; then rotate
the valve adjuster dial clockwise until the end is
seated in the tappet adjuster screw.
B. While holding the valve adjuster dial in place, use
the valve adjuster handle and loosen the jam nut;
then rotate the tappet adjuster screw clockwise
until friction is felt.
C. Align the valve adjuster handle with one of the
GZ063
marks on the valve adjuster dial.
D. While holding the valve adjuster handle in place,
rotate the valve adjuster dial counterclockwise
until proper valve/tappet clearance is attained.
 NOTE: Refer to the appropriate specifications in
Feeler Gauge Procedure sub-section for the proper
valve/tappet clearance.
 NOTE: Rotating the valve adjuster dial counter-
clockwise will open the valve/tappet clearance by
0.05 mm (0.002 in.) per mark.
E. While holding the adjuster dial at the proper clear-
ance setting, tighten the jam nut securely with the
valve adjuster handle.
F. Rotate engine 270° to the TDC position of the rear
cylinder; then repeat steps A-E for the rear cylinder.
3. Install the spark plugs and timing inspection plug; then
remove the cap screw from the crankshaft and install the
crankcase end cap.
 NOTE: Apply grease to the end cap to aid in installa-
tion.
4. Place the two tappet covers into position making sure
the proper cap screws are with the proper cover.
Tighten the cap screws securely.
Testing Engine
Compression
CC007D
 NOTE: The engine should be warm (operating tem-
perature) and the battery fully charged for an accurate
compression test. In the event the engine cannot be
run, cold values are included.
GZ059