Kubota RTV1140CPX, Руководство по ремонту

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ENGINE
RTV1140CPX, WSM
1-S42
Correcting Valve and Valve Seat
NOTE
• Before correcting the valve and seat, check the valve stem
and the I.D. of valve guide section, and repair them if
necessary.
• After correcting the valve seat, be sure to check the valve
recessing.
1) Correcting Valve
1. Correct the valve with a valve refacer.
2) Correcting Valve Seat
1. Slightly correct the seat surface with a 1.0 rad (60 °) (intake
valve) or 0.79 rad (45 °) (exhaust valve) valve seat cutter.
2. Resurface the seat surface with a 0.52 rad (30 °) valve seat
cutter to intake valve seat and with a 0.26 rad (15 °) valve seat
cutter to exhaust valve seat so that the width is close to
specified valve seat width (2.12 mm, 0.0835 in.).
3. After resurfacing the seat, inspect for even valve seating, apply
a thin film of lapping compound between the valve face and
valve seat, and fit them with valve lapping tool.
4. Check the valve seat with prussian blue. The valve seating
surface should show good contact all the way around.
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Valve Lapping
1. Apply compound evenly to the valve lapping surface.
2. Insert the valve into the valve guide. Lap the valve onto its seat
with a valve flapper or screwdriver.
3. After lapping the valve, wash the compound away and apply oil,
then repeat valve lapping with oil.
4. Apply prussian blue to the contact surface to check the seated
rate. If it is less than 70 %, repeat valve lapping again.
IMPORTANT
• When valve lapping is performed, be sure to check the
valve recess and adjust the valve clearance after
assembling the valve.
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Valve face angle
Factory
specifica-
tion
IN.
1.0 rad
60 °
EX.
0.79 rad
45 °
Valve seat angle
Factory
specifica-
tion
IN.
1.0 rad
60 °
EX.
0.79 rad
45 °
(1) Valve Seat Width (A) Check Contact
(B) Correct Seat Width
(C) Check Contact
(a) 0.26 rad (15 °) or 0.52 rad (30 °)
(b) 0.79 rad (45 °) or 1.0 rad (60 °)
(c) 0.52 rad (30 °) or 0.26 rad (15 °)
KiSC issued 05, 2014 A