If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterSpecial Tools and Sealant
Compression Gauge, 20 kgf/cm²:
57001-221
Valve Spring Compressor Assembly:
57001-241
Valve Spring Compressor Adapter,
25:
57001-1019
Valve Seat Cutter, 45° - 27.5:
57001-1114
Valve Seat Cutter, 45° - 32:
57001-1115
Valve Seat Cutter, 32° - 28:
57001-1119
Valve Seat Cutter ...
Crankshaft Removal
Split the crankcase (see Crankcase Splitting).
Remove:
Connecting Rod Big End Nuts [A]
Connecting Rod Big End Caps [B]
NOTE
Mark and record the locations of the connecting rods
and their big end caps so that they can be reassembled
in their original positions.
Remove the crank ...
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling
system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency
...