41
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.
Correct any high spots before assembly by continu-
ing to move the cylinder in a figure eight motion
until a uniform bright metallic finish is attained.
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.
Honing Cylinder
1. 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 measurements. The trueness (out-of-round-
ness) is the difference between the highest and low-
est reading. Maximum trueness (out-of-roundness)
must not exceed specifications.
CC127D
2. Wash the cylinder in parts-cleaning solvent.
3. 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.
CC390D
4. If any measurement exceeds the limit, replace the
cylinder.
Installing Top-Side
Components
A. Piston
B. Cylinder
1. Install the piston on the connecting rod making sure
there is a circlip on each side and the open end of the
circlip is directed upwards or downwards.
NOTE: The piston should be installed so the IN
mark is toward the intake (rear) side of the cylinder.
2. Place the two alignment pins into position. Place the
cylinder gasket into position; then place a piston
holder (or suitable substitute) beneath the piston skirt
and square the piston in respect to the crankcase.
3. Lubricate the inside wall of the cylinder; then using a
ring compressor or the fingers, compress the rings
and slide the cylinder over the piston. Route the cam
chain up through the cylinder cam chain housing;
then remove the piston holder and seat the cylinder
firmly on the crankcase.
4. Turn the cam chain tensioner screw clockwise to
retract the tensioner spring.
KM705
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.
CAUTION
The cylinder should slide on easily. Do not force the cyl-
inder or damage to the piston, rings, cylinder, or crank-
shaft assembly may occur.
