54
3. Place the cylinder on the surface plate covered with
#400 grit wet-or-dry sandpaper. Using light pressure,
move the cylinder in a figure eight motion. Inspect the
sealing surface for any indication of high spots. A
high spot can be noted by a bright metallic finish. Cor-
rect any high spots before assembly by continuing to
move the cylinder in a figure eight motion until a uni-
form bright metallic finish is attained.
WT580
4. Using a slide gauge and a dial indicator or a snap gauge,
measure the cylinder bore diameter in three locations
from top to bottom and again from top to bottom at 90°
from the first measurements for a total of six measure-
ments. The trueness (out-of-roundness) is the difference
between the highest and lowest reading. Maximum true-
ness (out-of-roundness) must not exceed 0.1 mm. Cylin-
der bore must not exceed 76.965 mm.
KC524
5. Wash the cylinder in parts-cleaning solvent.
6. Inspect the cylinder for pitting, scoring, scuffing, and
corrosion. If marks are found, repair the surface using
a #320 grit ball hone.
NOTE: To produce the proper 60° cross-hatch pat-
tern, use a low RPM drill (600 RPM) at the rate of 30
strokes per minute. If honing oil is not available, use
a lightweight petroleum-based oil. Thoroughly clean
cylinder after honing using soap and hot water. Dry
with compressed air; then immediately apply oil to
the cylinder bore. If the bore is severely damaged or
gouged, replace the cylinder.
WT579
7. If any measurement exceeds the limit, replace the cyl-
inder and piston.
Inspecting Cam Chain Guide
1. Inspect cam chain guide for cuts, tears, breaks, or chips.
2. If the chain guide is damaged, it must be replaced.
Measuring Camshaft Runout
NOTE: If the camshaft is out of tolerance, it must be
replaced.
1. Place the camshaft on a set of V blocks; then position
the dial indicator contact point against the shaft and
zero the indicator.
KC526
2. Rotate the camshaft and note runout; maximum run-
out must not exceed 0.05 mm.
Measuring Camshaft Lobe Height
1. Using a calipers, measure each cam lobe height.
ATV1013A
2. The lobe heights must be greater than 36.6 mm.
CAUTION
Water or parts-cleaning solvent must be used in con-
junction with the wet-or-dry sandpaper or damage to
the sealing surface may result.