Some trike kits offer an auxiliary fuel tank and some don't offer that option due to space reasons. The auxiliary tank has also been used in the 2-wheeler family of riders. There are certain complications involved with these EFI models and gravity feed is pretty much out of the question unless you want to mount a tank on top of your tour pack. There are various aftermarket manufacturers of auxiliary tanks out there, most of which just strap-on and resemble a piece of luggage. You still have the issue of getting the fuel into the tank as you cannot make any direct connection to the high pressure fuel lines on the EFI models. The reduced fuel mileage associated with a trike warrants a look at a reserve source of fuel for longer range, more so with those having 5-gallon tanks.
I have experimented with various tanks and delivery systems for quite some time and have a system that works for me. It's custom-made and some fuel-line and tank plumbing is required, but nothing that will damage or alter the stock fuel delivery components on the bike. I will be happy to share my design and help anyone considering the addition of an auxiliary fuel tank. My 1.5 gallons of reserve fuel has already came in real handy riding with my 2-wheel buddies sporting 6-gallon tanks and getting 40-plus mpg.
I have experimented with various tanks and delivery systems for quite some time and have a system that works for me. It's custom-made and some fuel-line and tank plumbing is required, but nothing that will damage or alter the stock fuel delivery components on the bike. I will be happy to share my design and help anyone considering the addition of an auxiliary fuel tank. My 1.5 gallons of reserve fuel has already came in real handy riding with my 2-wheel buddies sporting 6-gallon tanks and getting 40-plus mpg.