Honda BF40D Owner's Manual page 121

BF40D/BF50D Tune up
Spark plug gap
Idle speed
Valve clearance
Other specifications
0.024 0.028 in (0.6 0.7 mm)
850 50 rpm
Intake: 0.15 0.02 mm
Exhaust: 0.23 0.02 mm
TECHNICAL INFORMATION
No other adjustment is needed
See page 78
See shop manual
See shop manual
119