Suzuki GA413 Service Manual page 348

6A-42 ENGINE MECHANICAL
D Flatness of gasketed surface:
Using a straightedge and thickness gauge, check surface at a
total of 6 locations. If distortion limit, given below, is exceeded,
correct gasketed surface with a surface plate and abrasive pa-
per of about #400 (Waterproof silicon carbide abrasive paper):
place paper on and over surface plate, and rub gasketed surface
against paper to grind off high spots. Should this fail to reduce
thickness gauge readings to within limit, replace cylinder head.
Leakage of combustion gases from this gasketed joint is often
due to warped gasketed surface: such leakage results in re-
duced power output.
Limit of distortion: 0.05 mm (0.002 in.)
D Distortion of manifold seating faces:
Check seating faces of cylinder head for manifolds, using a
straightedge and thickness gauge, in order to determine wheth-
er these faces should be corrected or cylinder head replaced.
Limit of distortion: 0.10 mm (0.004 in.)