Kubota GL6000A-AU-B Workshop Manual page 107

GL6000A-AU-B, GL6000D-AU-B,GL9000A-AU-B, GL9000D-AU-B, WSM
Replacing Valve Guide
(When removing)
1. Press out the used valve guide using a valve guide replacing
tool. (Refer to "SPECIAL TOOLS".)
(When installing)
1. Clean a new valve guide and valve guide bore, and apply
engine oil to them.
2. Press in a new valve guide using a valve guide replacing tool.
3. Ream precisely the I.D. of the valve guide to the specified
dimension.
Valve guide I.D.
Factory specification
(Intake and exhaust)
IMPORTANT
• Do not hit the valve guide with a hammer during
replacement.
(A) When Removing
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.
Valve face angle Factory specification
2) Correcting Valve Seat
1. Slightly correct the seat surface with a 0.79 rad (45°) valve seat
cutter (Code No. 07909-33102).
2. Fitting the valve, check the contact position of the valve face
and seat surface with prussian blue. (Visual check) [If the valve
has been used for a long period, the seat tends to come in
contact with the upper side of the valve face.]
3. Grind the upper surface of the seat with a 0.26 rad (15°) valve
seat cutter until the valve seat touches to the center of the valve
face (so that (a) equals (b) as shown in the figure.).
4. Grind the seat with a 0.79 rad (45°) valve seat cutter again, and
visually recheck the contact between the valve and seat.
5. Repeat steps 3 and 4 until the correct contact is achieved.
6. Continue lapping until the seated rate becomes more than 70 %
of the total contact area.
Valve seat angle Factory specification
(1) Valve Seat Cutter
(A) Check Contact
(B) Correct Seat Width
(C) Correct Seat Surface
(D) Check Contact
1-S45
ENGINE
6.010 to 6.025 mm
0.2367 to 0.2372 in.
(B) When Installing
9Y1211607ENS0069US0
0.79 rad
45°
0.79 rad
45°
(a) 0.26 rad (15°)
(b) 0.79 rad (45°)
(c) Valve Seat Width
(d) Identical Dimension
9Y1211607ENS0070US0
KiSC issued 06, 2016 A