Honda CRF50F Owner's Manual page 141

Engine Specifications
Valve clearance Intake:
(cold)
Exhaust:
Spark plug CR6HSA (NGK)
U20FSR-U (DENSO)
(standard)
Spark plug CR5HSA (NGK)
(cold climate; U16FSR-U (DENSO)
below 5°C, 41°F)
Spark plug CR7HSA (NGK)
(extended high U22FSR-U (DENSO)
speed riding)
Spark plug gap 0.024 0.028 in
(0.60 0.70 mm)
Idle speed 1,700
Power Transmission
0.002 in Primary reduction
(0.05 mm) Gear ratio, 1st
0.002 in 2nd
(0.05 mm) 3rd
or Final reduction
Final drive
or
or
100 rpm
Specifications
4.058
3.272
1.667
1.190
2.642
chain
133
Technical Information