3-23
3
Measuring Camshaft Lobe Height
1. Using a calipers, measure each cam lobe height.
ATV1013A
2. The lobe heights must not exceed minimum
specifications.
Inspecting Camshaft Bearing
Journal
1. Inspect the bearing journal for scoring, seizure
marks, or pitting.
2. If excessive scoring, seizure marks, or pitting is
found, the cylinder head assembly must be
replaced.
Measuring Rocker Arm
(Inside Diameter)
1. Using a dial calipers, measure the inside diame-
ter of the rocker arm.
2. Acceptable inside diameter range must be
within specifications.
Measuring Rocker Arm Shaft
(Outside Diameter)
1. Using a micrometer, measure the outside diame-
ter of the rocker arm shaft.
2. Acceptable outside diameter range must be
within specifications.
Installing Valves
1. Apply grease to the inside surface of the valve
seals; then place a lower spring seat and valve
guide seal over each valve guide.
2. Insert each valve into its original valve location.
3. Install the valve springs with the closest coils
toward the cylinder head.
ATV-1011A
4. Place a spring retainer over the valve springs;
then using the valve spring compressor, com-
press the valve springs and install the valve cot-
ters.
KM717A
PISTON ASSEMBLY
NOTE: Whenever a piston, rings, or pin are out
of tolerance, they must be replaced.
Cleaning/Inspecting Piston
1. Using a non-metallic carbon removal tool,
remove any carbon buildup from the dome of
the piston.
2. Inspect the piston for cracks in the piston pin,
dome, and skirt areas.
3. Inspect the piston for seizure marks or scuffing.
Repair with #400 grit wet-or-dry sandpaper and
water or honing oil.
NOTE: If scuffing or seizure marks are too deep
to correct with the sandpaper, replace the piston.
4. Inspect the perimeter of each piston for signs of
excessive “blowby.” Excessive “blowby” indi-
cates worn piston rings or an out-of-round cylin-
der.
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Summary of Contents for DVX 250 2007
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