Cylinder Head Flaw; Valve Recessing; Clearance Between Valve Stem And Valve Guide - Kubota B2410 Workshop Manual

1 ENGINE
82410· 82710· 82910 WSM, 12271
Cylinder Head Flaw
1. Prepare an air spray red check (Code No. 07909-31371).
2. Clean the surface of the cylinder head with detergent (2).
3. Spray the cylinder head surface with the red permeative liquid
(1). Leave it five to ten minutes after spraying.
4. Wash away the red permeative liquid on the cylinder head
surface with the detergent (2).
5. Spray the cylinder head surface with white developer (3).
6. If flawed, it can be identified as red marks.
RC-AA
8
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(1) Red Permeative Liquid
(2) Detergent
(3) White Developer
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0
° oC
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Valve Recessing
1. Clean the cylinder head surface, valve face and valve seat.
2. Insert the valve into the valve guide.
3. Measure the valve recessing with a depth gauge.
4. If the measurement exceeds the allowable limit, replace the
valve.
5. If it still exceeds the allowable limit after replacing the valve,
correct the valve seat face of the cylinder head with a valve seat
cutter (Code No. 07909-33102) or valve seat grinder.
6. Then, correct the cylinder head surface with a surface grinder, or
replace the cylinder head.
0.05 (protrusion) to
Factory spec.
0.15 (recessing) mm
0.0020 (protrusion) to
Valve recessing
0.0059 (recessing) in.
Allowable limit
0.40 (recessing) mm
0.0157 (recessing) in.
(1) Cylinder Head Surface (A) Recessing
(B) Protrusion
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+
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Clearance between Valve Stem and Valve Guide
1. Remove carbon from the valve guide section.
2. Measure the valve stem 0.0. with an outside micrometer.
3. Measure the valve guide 1.0. with a small hole gauge, and
calculate the clearance.
4. If the clearance exceeds the allowable limit, replace the valves. If
it still exceeds the allowable limit, replace the valve guide.
Factory spec.
0.035 to 0.065 mm
Clearance between
0.00138 to 0.00256 in.
valve stem and valve
guide
Allowable limit
0.10 mm
0.0039 in.
Valve stem
0.0.
Factory spec.
6.960 to 6.975 mm
0.27402 to 0.27461 in.
Valve guide 1.0.
Factory spec.
7.010 to 7.025 mm
0.27599 to 0.27657 in.
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1-S32