Bearly Flying's Aux Fuel Tank

I recently posted some pictures of my bike with an Auxiliary Fuel Tank on it. Several Members have asked questions about it, so I thought I would provide a little more detail.

I talked to the Welding Shop that did the welding for me, and They "MAY" be interested in doing some more.

Anyone interested drop me a PM and I can talk to them in more detail.

I had previously looked at some of the Fuel Cell's presently available and didn't really like having something mounted too high or too far back on the bike due to the effects on handling.

Since the Wife wasn't interested in doing any L/D rides, I started looking at the passenger seat area.

Using some scrap wood I made a rough Mock up:



I bought a sheet of 1/8 Aluminum Plate and started laying out the tank starting with the base plate;





I had calculated the dimensions of the tank to end up with about 15.8 liters of volume(4.1 US gal), But when I cut some of my side pieces, the angles didn't match and I ended up having to grind off a bit to get things to fit. So the volume worked out to about 14.5 liters (3.8 US gal) The tank has 2 baffles inside forming a X from side to side that also function as stiffeners for the side walls.



I insulated the exterior of the tank with self adhesive reflective insulation to minimize any heat gain and expansion of the gas after fueling up. The Wife sewed up a cover using some scrap upholstery material she had, purposely stayed away from Black material to minimize heat again.

The tank sits fairly low on the bike in relation to the Main Fuel Tank, so I decided to install a fuel pump. I went to the local Auto Parts and picked up a relatively cheap 12 V fuel pump and fittings for a quick connect.

At the rear of the Passenger Seat compartment below the tail lights there is enough room ( after a little trimming with a Dremel) to install the fuel pump. (Fuel pump can be seen just behind the coil cord)



So the final product installs easily (Two Bolts and one quick connector) Used the tank all last summer, WFO in Park City UT and EOM in Lewisburg WVA.

Depending on my right wrist, I get between 750 to 800 km's ( 460 to 500 miles) maximum range. The additional weight of the tank and fuel is not even noticeable when riding.



So IF theres any interest, post up or PM me and I will see what kind of numbers My Welder can come up with.

For a minute there I thought you were going to say you built it outa balsa.

I think somebody's gonna get real busy.

:jester:

Goddammit Bust, Given away all my trade secrets.

Yup! an for ten bucks, I'll sell 'em the video.

:jester:

I guess balsa can soak up fuel. Gotta have a hell of a pump to suck it outta the balsa, though.

Where'd you tap into the factory fuel lines/tank to feed in from the aux tank?

Nice job! Too bad I'm a bit gunshy on dropping coin on Fuel Cell's at the moment...

Groo said:

Nice job! Too bad I'm a bit broke from dropping coin on Fuel Cell's at the moment...

Click to expand...

Fixed it for ya....

Consider me moderately interested.

Jazzzzz;

With the FJR being fuel injected and the pump mounted inside the tank, You pretty much have to install a bulkhead fitting into your main tank. There is an excellent article dealing with the install: Bulkhead Install

Not really that hard to do.

Groo: No problem, good luck.

Toe: Duly noted.

I'm interested too.

Jazzzzz said:

Where'd you tap into the factory fuel lines/tank to feed in from the aux tank?

Click to expand...

Apologies if this is a stupid question, but does using an aux feul pump mean you don't have to do as many mods to the OEM tank, i.e. just a tap and not the more elaborate stuff i've seen posted up on the forum.

Oh yeah, I'm interested too.

JamesK, not a stupid question at all. The aux fuel pump is only used to transfer to the main tank. The Aux Tank sits quite low in relation to the main tank, so rather than rely on gravity as a higher mounted Fuel Cell would, I chose to use a pump. The pump cost about $40 and is available at most Auto Parts stores. It's just a generic in line 12 V fuel pump.

Normally after fueling up, I will ride until the first bar on the fuel gauge goes out, open the valve, turn on the pump until the first bar of the fuel gauge lights up again. That allows some room for the fuel to expand as it heats up from the sun, etc. When the fuel guage gets below 1/2 a tank, I open the valve again and turn on the pump, transferring the remaining fuel to the main tank. That will pretty well refills the main tank to full again.

Bearly Flying said:

JamesK, not a stupid question at all. The aux fuel pump is only used to transfer to the main tank. The Aux Tank sits quite low in relation to the main tank, so rather than rely on gravity as a higher mounted Fuel Cell would, I chose to use a pump. The pump cost about $40 and is available at most Auto Parts stores. It's just a generic in line 12 V fuel pump.
Normally after fueling up, I will ride until the first bar on the fuel gauge goes out, open the valve, turn on the pump until the first bar of the fuel gauge lights up again. That allows some room for the fuel to expand as it heats up from the sun, etc. When the fuel guage gets below 1/2 a tank, I open the valve again and turn on the pump, transferring the remaining fuel to the main tank. That will pretty well refills the main tank to full again.

Click to expand...

Thanks for the explanation, another question, why not leave the aux tank valve open at all times, and only switch on the aux fuel pump when needing to move gas into the main tank. Alternately, why not have an eclectic valve/solenoid that works of the same switch as the aux pump?

I suppose you could do that if you wanted. Just more chance for a failure IMHO.

I close the valve to ensure it doesn't backflow, piece of grit or something in the pumps check valve?????? And if your overflow/vent lines aren't at the same level, one tank can overfill the other causing a spill .

Sometimes the main tank can pressure up due to heat build up from the engine and a restricted vent.

It's no big deal to reach back and flip the lever and turn on the switch.

Don't question the canuck, james. If we're puttin' canadien parts on our space shuttle then they probably know what they're talkin' bout.

Very nice work.

So far this is a GenI solution right?

How are you fastening it to the frame?

Yes it's on a 05 ( the fast ones)

The bottom rear of the tank has a socket built in that slides over the rear seat mount, The front of the tank mounts to the existing side panel bolts at the rear of the Drivers seat on each side.

I think if you managed to get the capacity up closer (or slightly above) 4.5 gallons, you'd have a real winner there!

vectervp1 said:

I think if you managed to get the capacity up closer (or slightly above) 4.5 gallons, you'd have a real winner there!

Click to expand...

He's already got a winner...it's already on his bike and he is using it. :clapping: