a motorcycle grade (moly free for the clutch) 20w-50 JASO rated oil would be great dont use car oil. you could ruin your clutch
A Honda 400ex is rated to hold 5 quarts of motor oil. This includes the oil stored in the oil pan and the filter which are replaced during an oil change.
about 2 qt.
2.3 quarts
10w-40 G4
GN4 Honda oil only.
1.9 US qts. Be sure to drain oilpan AND crankcase when changing oil.
1.9 us quarts
2.6 quarts
2.6 Quarts
on the right side of the motor there is a cap with twwo bolts take that off and theres th oil filter it will have a oil line running to it
On a 400ex the engine and transmission share the same oil. So when you change the oil in the engine you are changing the transmission oil as well. That is why you need an ATV or motorcycle oil designed for wet clutches.
10W30 or 10W40 motorcycle oil is recommended by Honda.