Second gas tank

[wics51]

I'm thinking about adding a second gas tank to my VW trike. Right now it has a 5 gal. harley tank mounted in the normal motorcycle position. I want to add an 8 gallon tank behind the rear seat. (spun aluminum tank). What kind of things do I have to worry about? It will be higher than the existing tank, If I T into the fuel line, will it try to back flow into the lower tank? Can I just T into the existing line? As you can tell, I'm new to this. I appreciate any help ya'll can give.
Wick

[champsman97045]

In a lot of ways it is just like any dual tank pick-up truck, you need a valve to keep the higher tank from draining back to the lower tank, it could be as simple as a brass valve mounted close at hand to be opened when the high tank gets real low or waiting till it goes empty and quickly opening the 2nd tank , there are a lot of ways to do it. Most pick-ups use a eceltric tank switch which opens one tank at a time.
Hope this might help

[Loner]

Put a 'check' valve in the line close to each tank (two separate check valves) and then 'T' them together. The check valves keep the fuel from feeding from the higher tank to the lower tank and so long as the feed lines are T'd together at a point lower than both you will get full fuel feed from both tanks before running out. Check valves are cheap and this will make an effective way to avoid the manual valve(s).

[1550vt]

I installed an electric fuel pump to pull fuel from my high-tank to my low tank. This pump has built-in check valves. When my front gets low...I just hit the button and pump it on out of the high tank. It would gravity flow, but since the pump will not let anything pass either way unless it is on....it was the easiest thing to do.

Like above....there are several ways to do this, but the fewer valves and connections involved, the better off you are.

[Charlie]

this what you need, they go for about 25 - 30 bucks for a good one

Amazon.com: Moeller Fuel Tank Three-Way Valve (3/8", Brass): Sports & Outdoors

[wics51]

Thanks, for the input, I appreciate it much. This is definitely a good option. Now just to figure out how to plumb it all.
Thanks
Walt

[wics51]

Thanks for the reply, I really like this option. I have an electric fuel pump in my spare parts. Where do you tie it in to the existing tank?

Did you have to install another bung in the tank? Sorry to ask so many questions, but I have to, I'm just an ol' dummy, but I'm learning!

[kj5ix]

Thanks for the reply, I really like this option. I have an electric fuel pump in my spare parts. Where do you tie it in to the existing tank?
Did you have to install another bung in the tank? Sorry to ask so many questions, but I have to, I'm just an ol' dummy, but I'm learning!

There should be an outlet on the bottom. add a hose to the pump, and another to where ever you are going to tie into the other tank or line. This one of on my Venture. You can put the pump almost any where. Use a filter on the input side of the pump too.

[1550vt]

Do some checking on what type of fuel pump you have...they may not all have a built in feature of the check-valves. If yours don't, all you have to do is to install one to prevent fuel from flowing down from the high tank to the low tank under gravity. You can obtain them in certain "crack" pressure ratings that will prevent this. Mine is an in-line high pressure pump. It's pretty simple....just plumb the pump in-line from your high tank down to your low tank. I found a plug in the bottom of mine and used that, but like said above....anyway you can get the fuel to pump into the tank will work, but you do have to be careful if you are running carb/carbs. If you plumb the output of the pump in such a manner that it is tied to your main fuel line feeding the carb/carbs....it may produce enough pressure to lift the float seat.

PM me with your e-mail address and I will send you a diagram and some pictures of my set-up.