Budget Fuel Cell


Premier Member
IBA Member
I scored this RCI cell on ebay for $90 shipped.

It has a usable capacity of about 3.5 gallons. The flush cap/flange assembly was terribly hard to use and also leaked. The vent line rollover valve protruded a couple of inches into the tank and spit gas onto the pavement when the bike was on the sidestand.

So I opted for this 45° billet filler from Speedmaster. Excellent Quality.

I wanted to give the vent as much altitude in the tank as possible but I didn't want it hanging off the filler neck as I have often seen. I decided to "tap into" the unused 8AN fitting in the bottom of the tank. Literally. I tapped the fitting to 1/8"NPT from the inside. Then I installed a 1/8" nipple and 1/4" compression fitting and ran 1/4" aluminum tubing up inside of the filler neck to the absolute highest point just below the cap.
Sorry, no flash pictures from inside the tank. :O

The frame is constructed of 1 1/4" flat iron and connects to my existing homemade side and top case brackets.

I applied heavy duty automotive exterior molding tape around the perimeter. Very strong. I also lashed the tank to the frame with 36" hose clamps covered in 1/2" shrink tubing.

The ball valve is from Maple Farkles. $15 shipped. It comes with 3 handles. The lever pictured is most convenient.

I used this 1/4" hydraulic hose coupler from Tractor Supply. $20

The bulkhead fitting also came from Maple. $20 shipped.

I always intended to add a stem to the bulkhead fitting inside reaching upward slightly to prevent the tank draining completely in the event the transfer line is ever severed. I also wanted the ability to see the fuel transfer in progress. The stem turned out to be a necessity in getting the bulkhead fitting to the hole.

I had to remove the tiny reed valve (behind the black plastic cover) in the cap. it was so sensitive it allowed the tank to hold enough pressure to prevent the gravity feed transfer. Now the cap vents both ways.

After some trail and error the system works well. I now have a total fuel capacity of 8.5 gallons. Transfer takes about 20 minutes. All told, this project came in at just under $250. My best advice is to choose your brass fittings wisely - they add up quick.


Premier Member
IBR Finisher
Some interesting ideas. I would caution you to keep an eye on the filter. You may find that a plain plastic filter is more durable and less prone to issues than the glass re-useable filter is. Watch for leaks from vibration there. You might also consider turning the filler neck 90º to the 'uphill' side of the tank when it's on the side stand. This will make filling slightly easier, as well as allowing your pelican case to open a bit more. I hope it works well for your needs. Good job on creating a nice clean system for a budget price and doing it yourself. :)

Clive Rand

Premier Member
I had thought of something similar, my thought was to tap into the balance tube at the front of my tank as a transfer point,not sure how this will work just yet, I have also considered the idea of pumping the fuel from the cell into the tank, so when the main tank is really low I can tranfer it rather quickly, with a solenoid instead of a ball valve, but this idea in its simplicity may be a much better idea.


Premier Member
IBR Finisher
Once you start using a fuel cell you will learn what technique works best for your system. Gravity feed systems are typically used before the main tank gets low, due to the time required for fuel to transfer. On both of mine I would ride around 100 miles and then open the aux tank's valve. Fuel would flow into the main tank until they equalized at which point both tanks would drain together as the bike used fuel. At Reserve on the main tank, my flat bed fuel cells were empty, so the valve could be shut prior to re-fueling.

Fittings - Brass dry break fittings can be found at marine supply stores for a reasonable price. Nissan and Chrysler Force styles work well. I would caution anyone using a fuel cell to never, ever use plastic dry break fittings. These, especially the BMW ones, are known failure points. Second, regardless of what you choose to use, BUY TWO SETS. I cannot stress this enough. Carry a spare set. This will save you a great deal of stress and time if you suffer a leaky o-ring. It does happen. Usually after a disconnect/re-connect, but sometimes just happens.

Make sure you plumb your fuel line to the aux cell to avoid excess length and keep it as low and even as possible to avoid air bubbles in the line. Also, make sure you have the ability to raise the tank! Typically this means disconnecting the dry break fitting first, but ensure there is enough clearance for the hose movement when you pivot the tank up. If you need to go hunting under the tank for a problem while on the road, this will save you a lot of headaches.

In regard to racks or frames for the fuel cell. If you are butt welding a tab or piece of the frame, it would be a Good Idea™ to place a gusset under that butt weld that spans the weld a reasonable amount. Gas weighs ~6.3 pounds per gallon. Add in the weight of the fuel cell and you have a fair amount of weight stressing your welds. Keep that in mind. Many a rough road has cracked welds on brackets. Having a fuel cell un-useable due to a rack failure sucks. Especially in rally mode.

Solenoids & pumps sometimes allow fuel to flow under gravity, despite being closed/off. Put a ball valve in your system too, even if you choose to run a solenoid and pump. You'll never regret having it there.