KTM 390 Duke Series 2019 Owner's Manual page 210

18 SERVICE WORK ON THE ENGINE
208
Danger
Danger of poisoning Exhaust gases are toxic and inhal-
ing them may result in unconsciousness and death.
–
Always make sure there is sufficient ventilation
when running the engine.
–
Use effective exhaust extraction when starting or
running the engine in an enclosed space.
–
Start the engine and check for tightness.
Finishing work
–
Check the engine oil level. ( p. 202)