TOHATSU BFT 250A, Руководство по обслуживанию

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CYLINDER HEAD
VALVE SEAT RECONDITIONING
Thoroughly clean the combustion chambers and valve
seats to remove carbon deposits. Apply a light coat of
Prussian Blue compound or erasable felt-tipped marker
ink to the valve faces [1].
Insert the valves, and then lift them and snap them
closed against their seats several times. Be sure the
valve does not rotate on the seat. The transferred
marking compound will show any area of the seat that
is not concentric.
Using a 45° cutter, remove enough material to produce
a smooth and concentric seat. Follow the valve seat
cutter manufacturer’s instructions.
Turn the cutter clockwise, never counterclockwise.
Continue to turn the cutter as you lift it from the valve
seat.
Use the 30° – 32° and 60° cutters to narrow and adjust
the valve seat so that it contacts the middle of the valve
face.
The 30° – 32° cutter removes material from the top
edge.
The 60° cutter removes material from the bottom edge.
Be sure that the width of the finished valve seat is within
specification.
[1]
VALVE SEAT RECONDITIONING TOOLS
Valve seat cutter, #608 45°
Solid pilot bar, 5.5 mm
T-wrench, #505
Accessory package, #246
Valve seat cutter, #607 30°
(Commercially available)
Valve seat cutter, #270 60°
CONTACT TOO LOW
CONTACT TOO HIGH
30°
60°