Kohler XT775 [40/56] Disassembly inspection and service
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Kohler XT775 [40/56] Disassembly inspection and service

Kohler XT675 [40/56] Disassembly inspection and service
40
Disassembly/Inspection and Service
KohlerEngines.com 14 690 01 Rev. G
Remove Valve Assembly
NOTE: Only intake valve has a seal. There is no valve
seal on exhaust side.
1. Push down on valve spring keepers to release valve
springs from valve stems.
2. Remove valve spring keepers and springs.
3. Push end of intake valve to release valve seal.
4. Remove both valves from opposite side of head.
Inspection and Service
Hard starting, or loss of power accompanied by high fuel
consumption, may be symptoms of faulty valves.
Although these symptoms could also be attributed to
worn rings, remove and check valves rst. After removal,
clean valve heads, faces, and stems with a power wire
brush. Then, carefully inspect each valve for defects
such as warped head, excessive corrosion, or worn stem
end. Replace valves found to be in bad condition.
Valve Guides
To check valve guide-to-valve stem clearance,
thoroughly clean valve guide and, using a split-ball
gauge, measure inside diameter. Then, using an outside
micrometer, measure diameter of valve stem at several
points on stem where it moves in valve guide. Use
largest stem diameter to calculate clearance. If intake
clearance exceeds 0.047 mm (.0018 in.) or exhaust
clearance exceeds 0.082 mm (.0032 in.), determine
whether valve stem or guide is responsible for excessive
clearance.
Maximum (I.D.) wear on intake valve guide is 5.512 mm
(0.2170 in.), while 5.512 mm (0.2170 in.) is maximum
allowed on exhaust guide. Guides are not removable. If
guides are within limits but valve stems are worn beyond
limits, replace valves.
Valve Seat Inserts
Hardened steel alloy intake and exhaust valve seat
inserts are press tted into cylinder head. Inserts are
not replaceable, but they can be reconditioned if not too
badly pitted or distorted. If seats are cracked or badly
warped, cylinder head should be replaced.
Recondition valve seat inserts following instructions
provided with valve seat cutter (A) being used. Final cut
should be made with an 90° cutter as specied for valve
seat angle. With proper 45° valve face angle, and valve
seat cut properly (44.5° as measured from center line
when cut 90°) this would result in desired 0.5° (1.0° full
cut) interference angle where maximum pressure occurs
on valve face and seat.
Lapping Valves
Reground or new valves must be lapped in, to provide
a good seal. Use a hand valve grinder with suction
cup for nal lapping. Lightly coat valve face with ne
grade of grinding compound, then rotate valve on seat
with grinder. Continue grinding until smooth surface is
obtained on seat and on valve face. Thoroughly clean
cylinder head in soap and hot water to remove all traces
of grinding compound. After drying cylinder head, apply
a light coating of engine oil to prevent rusting.

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