Auxillirary Fuel tank


Hey Org I've been wondering about this since I read a thread on here about the cannon ball run and driving coast 2 coast in so many hours. The guys did it in a BMW or something like that equipped with a secondary fuel tank in the trunk.

I remember we were on here talking about how it could be done faster on a busa but the frequent fill ups due to a 5gal. Tank would hinder progress.

My question 4 you technical guru's are is it possible to say put a fuel cell 1 or 2 gallon in the hump of a busa and somehow run it as a secondary tank? I know it's done in cars/trucks my buddy has an F150 with 2 fuel tanks but how would you set it up on a bike? My thoughts were say your buzzing down the highway and your fuel light comes on would there be a way 2 flick a switch and run off the fuel cell in the hump?

Figured this might be a good discussion of hypothetical and who knows somebody may even try it? It just piqued my curiosity and I want to know if it can be done and what would be needed?

Ready....Set....Go!!!! :laugh:
Yes it can be done, weld up a custom tank for the trunk with a secondary pump to fill the main tank when it gets low
Ok so you can buy a fuel cell and let's just say an walboro external fuel pump. But how would you activate it and how would you run your fuel lines and such? I imagine your gonna need an FPR and fuel filter as well.
Idk? That's why I'm trying to figure out the technical aspects of it. I've searched around and I haven't come across anybody who has done it or @ least that I could find. I think it would be a cool mod to do 4 riders who do a lot of traveling and rack up a ton of miles. Adding 2 or 2.5 gallons of fuel would be pretty convenient IMO :beerchug:

I'm not that technical so I'm wondering how to be able 2 switch fuel supplies on the move? What would be the best and most reliable way to connect it with your existing fuel setup?
I have seen several guys rig up aux tanks for iron butt runs. I don't know much about the fuel system but I was thinking you could just add the aux tank and gravity feed the primary tank.
Yeah I've seen those setups I guess I was just trying to make things a little more difficult :laugh: I wanted a more cleaner looking setup.
Yeah I've seen those setups I guess I was just trying to make things a little more difficult :laugh: I wanted a more cleaner looking setup.

If you had a Gen II and did the trunk mod to the max and modified the hump it would be difficult to get two gallons of added fuel.

If I had the money and the time I'd go for it. Probably add two to three gallons of fuel and set up people along the way for stop and go fueling, but I'd hate to know what my back and azz would feel like after flying across the country. Not to mention scanners, etc. :laugh:

I few hundred and eighty mile an hour fly bys and the cell towers would be jammed with 911 calls :laugh:
Good info Dado :beerchug:

I wasn't able to find that last link just pics of guys with 5 gallon jugs strapped 2 their bikes and that wasn't gonna cut it 4 me. In my head I was picturing a small fuel cell mounted in the hump some braided hose and AN/push fittings. Guess I was over thinking it.

I still want 2 know how or if it is even possible to run an additional fuel pump and be able to switch between fuel supplies. Would you T it off or remove the internal pump all together block it off and then run a larger external fuel pump that could draw fuel from both sources @ once?
I don't know a darn thing about this fuel system. I'd guess that the fuel pump is sitting in a sump on the primary tank and basically sucking fuel in and pumping it out at pressure to feed the injectors and the beast. So my thinking is to just gravity feed the primary tank with an aux tank. Done and done.

I don't see where you would needed an additional fuel pump, filter, regulator, lines ...... just the aux tank and a feed line to the primary tank.

To answer your question. Install a complete secondary fuel system ..... additional fuel pump, filter, regulator, lines, tank. Wire in a relay DPDT in the fuel pump circuit, between the fuel pump relay and fuel pump. One side would go to the factory pump the other side would go to the secondary fuel pump and of course the switch to toggle the relay. The system might require check valves to keep one system from feeding the other. Haven't really thought about it because I really wouldn't go this route.

I hear you on the hidden and sexy, but this would be for a 12 hour ride :whistle:, not easing downtown for the girls to see ....... did I type that :laugh:

I was raised under KISS Keep It Simple Stupid :laugh:
Warchild used to post a lot of threads about his trips on the busa with an extra fuel tank with some custom mounts and a custom tailbag design to fit over it to hide it. Wish I was in front of a computer to look for it. Good luck on your search.!
If you were serious about these contests or really like to go a long time without filling up and have to have that sleek look where no one can see you have an additional 2-3 gallons, I would pay to have the hump itself converted to full time fuel cell duty. Fiberglass is used for fuel cells but of course you will have to gel coat it and use the special coating inside for reliability. It would be super easy to make a mold.

There are a few sheet metal crafters that could easily make a rear hump that fits like stock. Probably make it tad taller too for a few more ounces of fuel. I would suggest build a baffle system inside or better yet, use the fuel foam as it is cheaper. Even though it isn't your main supply, you will want a consistent draw from it with no starvation.

I really think the most you could fit in the hump assuming you add a little sump at the bottom is about 3 gallons. I would have to measure with one of my spare humps. Of course it's a Gen I and appears a little bigger than the Gen IIs.

You could spend the big bucks and get an aftermarket replacement gas tank. I think they are about 6-6.5 gallons as opposed to the stock 5.5 gallons.

One extra U.S. gallon right here. No extraneous plumbing, no butt ugly tank hanging out the back...

Just saying. :laugh::laugh::laugh:

Extra tank in the sub frame is doable. You wouldn't need an extra pump, regulator, steel lines ect.

Have a bung welded to the lowest part of the tank, and make sure the fuel cell is as high up as you can get it. You would also need to vent the cell otherwise the a vacume would start and hold the fuel in the cell and lines. You could vent it like the old water injection tanks with a check valve so under acceleration it would stay closed, but suction would pull it open when needed. I would T the line off the check valve in to the fuel tank vent. That would be the safest way to keep the fumes out of the tail, and if you had thermal expansion of fuel it would dump in a safe place.

That's how I would do it.