Zenith ZPP 416 - Replacing the Valve Seat Ring; Valve Seat Insert Oversizes; Replacing Valve Guide

CYLINDER HEAD ASSEMBLY EM -35
REPLACING THE VALVE SEAT RING
1. Cut away the inner face of the valve seat to reduce
the wall thickness.
0.3 - 0.6 mm
(0.0118 - 0.0236 in.)
0.3 mm (0.012 in. R)
0.15 - 0.3 mm
(0.006 - 0.0118 in.)
Old hole
A
B
Remove
D∅
New hole
H
ECA9281F
2. Enlarge the diameter of the valve seat so that it
matches the specified oversize hole diameter of the
new valv e seat ring.
3. Heat the cylinder head to about 250
C(480F) and
press - fit an oversize seat ring for the bore in the
cylinder head.
4. Using
lapping compound, lap the valve to the new
seat.
Valve seat contact width
Intake : 0.8 ~ 1.2 mm (0.0315 ~ 0.0472 in.)
Exhaust : 1.3 ~ 1.7 mm (0.0512 ~ 0.0670 in.)
VALVE SEAT INSERT OVERSIZES
Description
Size mm (in.)
Size
mark
Seat ring height H
mm (in.)
Oversize hole diameter
I.D. mm (in.)
0.3
(0.012) O.S.
30
5.1
~5.3(0.2008~0.2087)
30.
7~30.721 (1.2087~1.2095
Intake valve
Seat ring
0.6 (0.024) O.S.
60
5.4~5.6(0.2126~0.2205) 31.0~31.021(1.2205~1.2213)
0.3 (0.012) O.S.
30
6.2~6.4(0.2441~0.2520) 27.3~27.321(1.0748~1.0756)
Exhaust valve
Seat ring
0.6 (0.024) O.S.
60
6.5~6.7(0.2560~0.2638) 27.6~27.621(1.0866~1.0874)
REPLACING VALVE GUIDE
1. Using the special tool (09221-3F100 A/B), withdraw
the old valve guide toward the bottom of cylinder head.
2. Recondition the valve guide hole so that it can match
the newly press-fitted oversize valve guide.
Valve guide
Valve guide installer
(09221-3F100A)
Cylinder head
Valve guide installer
(09221-3F100B)
Valve guide installer
adapter
14mm (0.5512 in.)
ECDE109C
ZENITH POWER PRODUCTS - 416