So one of the recent additions by Rotax is the recommendation to have a return fuel line from the engine to the tank to ensure cool fresh fuel gets to the carbs. There are a couple of ways that you can plumb that line, but they all share a common requirement. You must put a restrictor somewhere in the line to ensure there is more fuel pressure going to the carbs than going down the return line. This takes the form of a “Pilot Jet” that is installed in either the Banjo bolt, or in the actual fuel T. In my case I was removing the 2 port fitting to go to the 1 port fitting. All I had to do was remove the pilot jet from the 2 port fitting and install it into the banjo bolt. Look at the attached pictures for details of how the jet fits into the system.

Then the actual return line is simply a section of 1/4″ fuel line that runs back to the top of the header tank behind the seat. This gives a slow trickle of fuel back to the tank when the engine is running.