Originally Posted by underPSI
Further investigating makes me think it's engine model specific based on the sub-model number (In your case -DS22 or FH601V-DS22). The two engines I'm ordering parts for are the -DS25 and -CS21 so I assume I don't need them since they are not listed.
*Note to others* When looking to see if your engine requires this additional part you need to check under the model number FH721V-####
My FH601V-DS22 does have an oil drain tube, but this extra long tube would likely be needed if
adding the oil cooler, if you view the illustrated parts breakdown diagram, the oil cooler mounts right where the drain tube and oil filter are located. You probably don't have to order it, but it must be easier to do oil changes or else it wouldn't be there. It would seem like it wouldn't be there if it was not needed, if you're (kawasaki) making engines all the identical except one or two parts to save money, any part not needed would be eliminated it seems. But as you said, check your specific sub-model number, some may vary.