Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionValve Seat Repair
Repair the valve seat with the valve seat cutters [A].
Special Tools - Valve Seat Cutter Holder Bar [B]: 57001
-1128
Valve Seat Cutter Holder, 4.5 [C]: 57001
-1330
[For Exhaust Valve Seat]
Valve Seat Cutter, 45° - 27.5:
57001-1114
Valve Seat Cutter, 32° - 28:
57001-1119
Valve Seat ...
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
...
Troubleshooting guide
Engine Does Not Start
Starter Motor Won’t Turn
Engine stop switch off
Transmission not in neutral
Fuse blown
Battery leads do not make good electrical
contact with battery terminals
Battery discharged
Engine Cranks, But Won’t Start
No fuel in tank
Fuel line clogged
Fuel ...