X-90 (2WD) L4-1591cc 1.6L SOHC MFI (1997)
1. Exhaust Valve Seat: Use valve seat cutters to make two cuts as illustrated in figure. Two cutters must be used: the first for making 15° angle, and
the second for making 45° angle. The second cut must be made to produce desired seat width.
Seat Width For Exhaust Valve Seat: 1.1 -1.3 mm (0.0433 - 0.0512 inch).
2. Intake Valve Seat: Cutting sequence is the same as for exhaust valve seats.
Seat Width For Intake Valve Seat: 1.1-1.3 mm (0.0433 - 0.0512 inch).
3. Valve Lapping: Lap valve on seat in two steps, first with coarse size lapping compound applied to face and the second with fine-size compound,
each time using valve lapper according to usual lapping method.
Cylinder Head
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Remove all carbon from combustion chambers.
NOTE: Do not use any sharp-edged tool to scrape off carbon. Be careful not to scuff or nick metal surfaces when decarboning. The same applies
to valves and valve seats, too.
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Check cylinder head for cracks in intake and exhaust ports, combustion chambers, and head surface.