TOHATSU BFT75A Service Manual page 392

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VALVE LENGTH/VALVE O.D.
Measure the overall length and the O.D. of the valve.
Overall length
STANDARD:
IN: 118.55 – 119.15 mm (4.667 – 4.691 in)
EX: 117.25 – 117.85 mm (4.616 – 4.640 in)
Valve O.D.
STANDARD:
IN: 27.85 – 28.15 mm (1.096 – 1.108 in)
EX: 22.85 – 23.15 mm (0.900 – 0.911 in)
If the measurement is less than the standard, replace
the valve with a new one.
VALVE GUIDE I.D.
Using the valve guide reamer (special tool), ream the
valve guides to remove any carbon deposits before
measuring.
• Turn the special tool clockwise, never turn it
counterclockwise. Continue to turn it clockwise as
you lift it from the valve guide.
TOOL:
Valve guide reamer, 5.5 mm [1]
Measure and record each valve guide I.D.
STANDARD:
IN/EX: 5.51 – 5.53 mm (0.217 – 0.218 in)
SERVICE LIMIT:
IN/EX: 5.55 mm (0.219 in)
If the measurement exceeds the service limit, replace
the valve guide with a new one.
• Check the valve stem-to-valve guide clearance after
replacing the valve guide.
VALVE STEM-TO-VALVE GUIDE
CLEARANCE
Calculate the gap between the valve stem O.D. and the
valve guide I.D.
STANDARD:
IN: 0.020 – 0.050 mm (0.0008 – 0.0020 in)
EX: 0.050 – 0.080 mm (0.0020 – 0.0032 in)
SERVICE LIMIT:
IN: 0.080 mm (0.0032 in)
EX: 0.110 mm (0.0043 in)
If the stem-to-guide clearance exceeds the service limit,
replace the valve guide with a new one (page 14-40).
If the stem-to-guide clearance exceeds the service limit
with new guides, replace the valves as well.
• Recondition the valve seats whenever the valve
guides are replaced (page 14-41).
07HAH-PJ7A100
CYLINDER HEAD
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