Toro 500 EFI Service Manual page 50

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.
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.
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.
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.
48

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.
4. If any measurement exceeds the limit, the cylinder
must be replaced.
Measuring Camshaft Runout
CC129D

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.
2. Rotate the camshaft and note runout; maximum tol-
erance must not exceed specifications.
Measuring Camshaft Lobe Height
1. Using a calipers, measure each cam lobe height.
CC127D
CC390D
CC283D