Well interesting questions.... the Jerry can is of course easier but as I said a like to build cool stuff.... I am going to test the pump tonight by building a mock up of the design. built in scale with the bike. So a 19ltr or more tank about 1/2 meter up and 2 meters away(compensating for actual fuel hose routing) and a 10ltr lower tank both with bottom fill and suction. The pump should still be able to move the fuel of in the test case water(water is heavier).... good food for thought.... I might just just pump the fuel to the top of the main tank via one line and a second line allow gravity to care fuel in the other direction. So thats pump aux to top of main and gravity bottom of Main to Aux.

another problem found is that I will need to protect the fuel line that pass between the sidecar and the motorcycle from the abuses of the outside world... I guess protective. pipe work or something must be made up as well.

Then again the possibility of a permanent tank with none permanent fuel lines is possible. Simply mount the pump and cut the fuel lines as needed and when needed place them into the tanks through the top openings and manually adjust the height for either direction of transfer by sliding less or more fuel line into the respective tanks. Doing it this way simplifies the build but complicates the actual use. I would also then not need the LEDs or the heavy pipe work for protection......

Huummmm.... where did I put that old Jerry Can