Kubota ZD25F User Manual

1-S29
ZD25F, WSM
ENGINE
(3) Servicing
(A) Cylinder Head and Valve
Cylinder Head Surface Flatness
1. Clean the cylinder head surface.
2. Place a straightedge on the cylinder head’s four sides and two
diagonal as shown in the figure.
3. Measure the clearance with a feeler gauge.
4. If the measurement exceeds the allowable limit, correct it with a
surface grinder.
IMPORTANT
• Do not place the straightedge on the combustion chamber.
• Be sure to check the valve recessing after correcting.
W10301620
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.
W10303200
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.
W10305870
Cylinder head surface
flatness
Allowable limit
0.05 mm
0.0020 in.
(1) Red Permeative Liquid
(2) Detergent
(3) White Developer
Valve recessing
Factory spec.
0.05 (protrusion) to
0.15 (recessing) mm
0.0020 (protrusion) to
0.0059 (recessing) in.
Allowable limit
0.40 (recessing) mm
0.0157 (recessing) in.
(1) Cylinder Head Surface (A) Recessing
(B) Protrusion
KiSC issued 04, 2009 A

Kubota ZD25F Specifications

General

Brand	Kubota
Model	ZD25F
Category	Lawn Mower
Language	English