Suzuki Wagon R Manual page 2232

Valve seat repair
A valve seat not producing a uniform contact with its valve or
showing width of seating contact that is out of specified range
must be repaired by regrinding or by cutting and regrinding and
finished by lapping.
1) EXHAUST VALVE SEAT: Use valve seat cutters (1) to make
two cuts as illustrated in figure. Two cutters must be used:
the first for making 22° 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
"a": 1.0 – 1.4 mm (0.0394 – 0.0551 in.)
2) INTAKE VALVE SEAT: Use valve seat cutters (1) to make
three cuts as illustrated in figure. Three cutters must be
used: the 1st for making 15° angle, the 2nd for making 60°
angle, and 3rd for making 45° angle. The 3rd cut (45°) must
be made to produce desired seat width.
Seat width for intake valve seat
"b": 1.0 – 1.4 mm (0.0394 – 0.0551 in.)
3) VALVE LAPPING: Lap valve on seat in two steps, first with
coarse size lapping compound applied to face and the sec-
ond with fine-size compound, each time using valve lapper
according to usual lapping method.
Cylinder head
• Remove all carbon deposits from combustion chambers.
NOTE:
Do not use any sharp-edged tool to scrape off carbon
deposits. Be careful not to scuff or nick metal surfaces
when decarbonizing. The same applies to valves and
valve seats, too.
ENGINE MECHANICAL (M13 ENGINE) 6A2-65