Honda CRF50F 2017 Owner's Manual page 104

ENGINE
Bore and stroke
Compression ratio
Displacement
Spark plug
Standard
For cold climate
(Below 5°C, 41°F)
For extended high speed
riding
Spark plug gap
Idle speed
Valve clearance (Cold)
39.0 × 41.4 mm (1.54 × 1.63 in)
10.0 : 1
3
49.4 cm (3.01 cu-in)
CR6HSA (NGK) or
U20FSR-U (DENSO)
CR5HSA (NGK) or
U16FSR-U (DENSO)
CR7HSA (NGK) or
U22FSR-U (DENSO)
0.60 – 0.70 mm (0.024 – 0.028 in)
-1
1,700 ±100 min (rpm)
Intake 0.05 mm (0.002 in)
Exhaust 0.05 mm (0.002 in)
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