KYMCO MXU 450i, Service Manual

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3-14
2. Remove the valve seal and the lower remaining
spring seat. Discard the valve seal.
CC134D
CC136D
„
NOTE: The valve seals must be replaced.
3. Remove the valve springs; then invert the cylinder
head and remove the valves.
Measuring Valve Stem Runout
1. Support each valve stem end with the V Blocks;
then check the valve stem runout using a dial indi-
cator.
ATV-1082
2. Maximum runout must not exceed specifications.
Measuring Valve Stem Outside
Diameter
1. Using a micrometer, measure the valve stem out-
side diameter.
2. Acceptable diameter range (intake valve) must be
within specifications.
3. Acceptable diameter range (exhaust valve) must
be within specifications.
Measuring Valve Face/Seat Width
1. Using a micrometer, measure the width of the
valve face.
ATV-1004
2. Acceptable width must be at or above specifica-
tions.
Measuring Valve Face Radial
Runout
1. Mount a dial indicator on the surface plate; then
place the valve stem on a set of V blocks.
2. Position the dial indicator contact point on the out-
side edge of the valve face; then zero the indicator.
ATV1082A
3. Rotate the valve in the V blocks.
4. Maximum runout must not exceed specifications.
Measuring Valve Guide/Valve Stem
Deflection (Wobble Method)
1. Mount a dial indicator and base on the surface
plate; then place the cylinder head on the surface
plate.
2. Install the valve into the cylinder head; then posi-
tion the dial indicator contact point against the out-
side edge of the valve face. Zero the indicator.