1999-2004 Honda TRX400EX FourTrax Service Manual, Page 45Get this manual
MAINTENANCE Pour the recommended oil (page 3-9) into the oil tank up to the upper level mark on the dipstickNOTE:
The engine takes about 1.85 liters (1.95 US qt, 1.63 Imp qt) at oil and filter changeBecause only portion of that oil is held in the oil tank, you cannot add the full amount initially
OIL CAPACITY:
1.8 liters (1.9 US qt, 1.6 Imp qt)at draining 1.85 liters (1.95 US qt, 1.63 Imp qt) at draining filter change 2.2 liters (2.3 US qt, 1.9 Imp qt) at disassembly
FILLER CAPIDIPSTICK
Install the oil filler capldipstickPlace the vehicle on firm level groundStart the engine and let it idle for few minutes without snapping the throttleStop the engine and add the recommended oil up to the upper level mark on the dipstickInstall the filler capldipstickStart the engine and recheck the oil level (page 3-91After replacing, make sure there are no oil leaks