Super Tenere Fuel Cell

I wanted a fuel cell for my Super Tenere due to getting a draw in the '13 Iron Butt Rally. I also find it very handy when riding in shorter endurance rallies and traveling in Alaska, Eastern OR/WA, etc where fuel is not always available at night. (OR doesn't have 24 hour pumps, for example, and a lot of the small stations in the high desert East of the Cascades have folded in the tough economy.) My friend Ernie A. offered to make one up for me and I finally got a chance to go up to Portland, OR and work with him on the project that culminated in the design and item you see below.

I've had fuel cells on my previous FJR, both a Jazz 4.25 Gal generic cell and a custom Tanji Flat Bed fuel cell that was 4.8 Gal. Fuel cell use is not new to me.

My general needs were:

- double my range to reserve (real world, I'm getting 360-400 miles before reserve now, depending on conditions and speeds. Most of the trip home was at 70-80 mph speeds).

- have a load platform that I could strap things to

- An accessory rail to mount a flashlight to the side

- my roll of duct tape over the filler neck

- A filler neck location that would allow me to fill the tank while seated on the bike, (arguments exist for and against this procedure, but it's my preference)

- have a design that would pass IBR technical inspection.

All of those needs were met with this design.

Ernie also has another design that is mounted in the pillion seat location and leaves the rear open for luggage. Intended to work with AltRider rear racks and the oem one. That design is perfect for those riders that have occasion to carry a passenger and want to easily remove the fuel cell when not needed. It's a tad over 5 gal capacity.

Ernie can customize fuel cells to your needs. Nothing in this for me, I'm just really, really happy with my fuel cell and wanted to share this with the ST guys.

www.eazcycle.com for contact info, but the web site is still under construction.

Pics:

In fabrication progress


Painting, (chose to paint instead of anodize or powder coat due to time constraints, but both of those options are available.)



Finished cell on bike. 4.8 Gal. Works great, gives me a 400 mile range on the bike, conditions and speeds being variable.







Dimensions: The fuel cell is essentially a 13" x 23" x 4.5" box. The load platform overhangs the sides and back by 1" with 5/16" slots for straps or bungie cords. The front fence sticks up 1" so loads will not slide forward. This fence could be taller and incorporate a back rest or pad if so desired. While the basic design is established, custom touches are up to the customer to come up with and personalize with the fabricator. This cell is made from .125" wall aluminum throughout.

Fitting at rear right corner is a tip over valve as well as vent. A check ball prevents fuel loss if the bike is on it's side or worse. The flash light holder is something I wanted, but this could be adapted for any accessory you have that fits in that area. Or simply drilled and tapped for some general purpose use, or deleted from the design. I wanted a very direct fuel line run, so did some minor modifications to the aluminum seat bracket and plastic trays to allow the fuel line to run as shown. The filter sits out behind the seat for excellent visual inspection and the marine drybreak fittings under the seat allow for quick removal of the fuel cell, if desired. The seat can still be used in the high or low positions. I used marine 5/16" fuel line which has a tough outer layer and normal rubber inner layer. Just a little extra durability and resistance to abrasion, etc. All fittings are 5/16" I.D. and the cap is a non-vented, DOT approved, tethered, ratcheting design, also sourced from Coyote-
Gear.

One of the really cool things about this fuel cell design is the minimum number of pieces involved. The front panel is one piece all the way down to the mounting tabs. The main bottom also has the sides as one piece, folded up and re-enforced with an internal weld. The back is just a single piece welded in. The top load platform is one piece with all the slots milled in. So the main tank is essentially four pieces. The neck is part purchase part that comes with the cap, the other is a 2" tube. They are not just butt welded together, but machined to press fit together, then welded. Tons of details involved in this tank. And it shows in the final results and how it performs.

Note that the fuel cell is bolted to the bike at four points, two up front and two in the rear that go thru tubes to spacers welded to the tank at the bottom. This is mounted with the factory rack in place, with four additional rubber pads in the rack holes for some buffer, but solid to the bike. Very solid. I was doing IBR tech last year and this easily passes inspection for the IBR. The volume of this tank, w/o air gap, is 5.0 gallons. This means that with the published capacity of the Super Ten at 6.1 gallons, plus 5 gallons of the fuel cell, (which you can't actually get into it), I am well under the 11.5 gallon maximum allowable capacity. This makes for a low stress tech inspection at the IBR for me. ::008::

I used a brass bulkhead fitting that took at 5/8" hole and has a 5/16" outlet to a hose barb. Sourced that at Oil Filter Service Company in Portland, OR, along with some o-ring washers. Was easy to install down low on the left side of the tank. This did require removal of the fuel pump assy, which requires separating the two halves of the assembly, which is not for the faint of heart. I taped a small cap from a spray bottle over the inside of the hole with some duct tape to catch most of the chips, then vacuumed out the few chips from the tank that escaped that. Deburr the hole well, and it helps to have a stubby ratchet and big sockets. Otherwise very strait forward.

Basic directions here for installing a bulkhead fitting - http://www.fjr1300.info/howto/bulkhead.html

I chose a Rustoleum mettalic paint to look fairly close to the finish on the Zega Pro side cases. Anodizing or powder coating in almost unlimited colors is possible if you have the time and $$. The paint was fast and easy and protects the aluminum from oxidizing. Dries to touch in 5 minutes, cures in 30 minutes. Made applying the 3 coats painless and fast. I installed plugs and masked them off as well as the fuel filler neck, (from Coyote-Gear, though they no longer show this item on their site), prior to painting. After paint, I installed the fittings with some Loctite 367 PST.

There is a small sump welded onto the tank that angles fuel down and gives a better mounting place for the valve than just a strait bung in the tank. This places it in easy reach on the side of the fuel cell. Since this is a gravity fuel cell design, (hey, it's a LAW), this keeps the gas always flowing down hill, which is a very good thing.

In practice, I fill both tanks at the gas station. I ride until the gas gauge shows 3/4 tank, (80-120 miles), then switch the fuel cell valve open. At this point it takes about 6 minutes for the gauge to return to the full indication, and it stays at full to 225-250 miles, then drops to 3/4 again. I suspect that shortly after it goes to 1/2 indication, the fuel cell is empty. When I stop for gas, I close the fuel cell valve, fill both tanks and repeat.

I plan to mount a hydration jug on the fuel cell for rally use. Currently I have one mounted at the foot peg, but would prefer it to be higher and not in the way when I paddle the bike around in parking lot or off pavement conditions.

Got questions? Ask em and I'll do the best I can to answer them, or ping Ernie.

That's a very very nice job! well done! I wish I could do the same...

Thanks! It works very well and I'm very happy with it. Ernie was really nice to work with and the results are just want I wanted.

Thanks, wasn't sure if Beasts or Modifications was most appropriate.

To answer some other questions not posted, the cell does have a cross baffle system inside to reduce effects of sloshing. With it's low profile this is not really an issue, but overkill is a good thing, and it's part of meeting the IBR rules for fuel cells.

This was a prototype, future units will likely have the metal water jet cut out and fabrication time should be reduced. ErnieA will have to speak to any questions on pricing, I'm just a happy customer.

Damn!...very nice!


.

Very nice indeed!

I really like your fuel cell and am considering it for my bike, but I have a cupple of questions.

Is it really necessary to drill the tank. Wouldn't it be easier (and in my case, safer) to tap into one of the fuel lines?

Where is the valve you "switch the fuel cell valve open" located? Why not leave it open all the time?

You have to drill the tank. The fuel lines are under high pressure for the Fuel injection system, so you need to feed the fuel into the unpressurized tank.

I've got a whole fuel cell setup (tank/filter/shutoff/quick disconnects) for my S10 (not nearly as nice as the one posted above!), but I'm also hesitant about drilling. I took it off my last bike that had a drain bolt in the tank, so I was able to simply screw a barb into that threaded hole.

I think he said the valve is right behind the seat, so he just reaches behind his butt to switch it open. The reason to leave it closed for a while is so the tanks don't try to level each other out when they're topped off, thus causing an overflow out of the lower of the two. I used to wait till my low fuel light came on, then popped the valve and watched the fuel gauge fill back up to the top.

As MikeF responded you really do need to drill the tank and put in a fitting. If you were to install a "T" fitting into the return line you would have to use a fuel pump and have a one-way check valve to keep the fuel system from back filling the Aux tank.

The valve on this tank is mounted to a small sump in the left front corner of the cell (the lowest point on the tank. It is within easy reach with the left hand and out of the way from something catching on it and turning it on/off when not needed. Here is a picture of it:

I'm working on a 5 gallon cell that sits on a plate under the pillion seat right now. This other design will allow for a easy on/off to switch back to giving a passenger a ride between longer trips.

Thanks for the comments on the fuel cell and I will be making more.

ErnieA
Milwaukie Oregon

(Hit myself in the forehead) Just when I figured out how to hold
7 Gator Aid bottles someone posts this.:ddog

There are some very talented fab people out there.

Just to check: 6.1 gallons in stock tank is 275 mile range +/- at 45 mpg US. (Optomistic, but some have gotten 48 mpg US average on long trips.)

13" x 23" x 4.5" is a volume of .7786 CF and at 7.48 gal/CF encloses a volume of 5.82 gallons, or 0.82 more than the 5.0 reported above. Is some of this space occupied by more than baffles? Or is this the "air gap" mentioned in your text?

6.1 + 5.8 = 11.9 gal (more than IBA limit?) or a 535 mile range at 45 mpg US.

The dimensions you cite are the outside measurements and the wall thickness is .125. In addition to the baffles there are two 1 inch tubes that are the rear mounts. Couple those three items with the air space and we have a tank with slightly less than 5 gallons, and well within the IBA/IBR rules.

Ernie

I will ignore the 45 mph mpg, as that's not realistic in rally mode, or pertinent to the discussion.

http://www.metaltanks.com/tank-capacity-calculators

.125" wall thickness, so we are talking about 12.75 x 22.75 x 4.0 + a volume of: 5 gal. 1/2" air gap is factored into the mix with the placement of the filler neck, (so you really don't have that 4.5" height, but 4.0 instead). IOW, the filler neck goes into the tank 1/2" so you can't actually fill things to the max volume. The tubes and baffles take up a tad more space, leaving you with the end results of ~ 4.8 gal of useable fuel.

Mikef pretty much nailed this. Drilling the tank is really not a big deal. I taped a cap under the hole after drilling a small pilot hole. Then used a Unibit to drill the hole out to the necessary size, catching 98% of the chips in the cap. Removed the cap and chips, deburred the hole carefully and then used a vacuum to suck out the chips I missed or were created during the deburr process, (which were minimal and mostly taken out bit by bit).

It helps to have done this before. But it also helps that I'm a machinist with 25 years of experience. My comfort level is pretty high with metal. Having also wrenched for a dozen years doesn't hurt either.

As long as your hole is not so close to the edge of the tank that you can't get a wrench on the nut on the inside of the tank, and your hands are small enough to fit into the tank, this is not rocket science. The fuel lines are not a good choice on a EFI bike. Every bike has different issues. HDs have a cross over line between the fat bobs, for example, that works well for aux fuel connection with gravity feed. On the Super Ten, you really need to drill the tank. It may be possible to drill the fuel pump plate, but I am much less comfortable drilling a hole into plastic unless I have a oem fitting to place there. That plastic is prone to cracking. It's not like it's UHMW with some fiber to hold it together.

As show in the pictures, (#7 in the original post), the valve is on the left side front corner of the tank. There is a small sump fitting there that keeps fuel flowing down hill at all times to and thru the valve. It's with in easy reach of my left hand while riding. If I left it open all the time, the potential to over flow the main tank exists.

This is pretty much true of most fuel cell designs. My wife's F650GS has the main tank under the seat with the fuel cell above the pass seat. It's rather ugly when she forgets to close the valve, fills both tanks and runs in to take a pee. When she comes out, there is a huge puddle of gas and the station attendant has hit the emergency cut off and called 911 and hazmat. That really adds to your fuel stop times.:huh

Great write up! I picked up some useful tidbits.

Thanks,

Jim

Havent done an IBA event in sometime now. But I always love to see gear that is specific to long distance riding especially something as nice & well thought out as your tank. Congrats on your draw for the Iron Butt! Let us know how you fair.

Update on the fuel cell. After four months of using it, including a trip to FL and back right after Xmas in sub freezing temps and some high temps back when I first got the cell, I've had zero issues with it. It just works! I'm still very pleased with the design and function of the cell.

Here are some pictures of a Pillion seat type cell that Ernie is also making for the Super Tenere. These are 5 Gal, if I understand correctly, but can be larger or smaller per customer requests. And no doubt adapted to other bikes as well.

or... swap in a diesel engine and your oem tank will take you nearly twice as far; albeit a we bit slower

but right engine still keeps up with traffic so cagers don't want to push you out of the way

There would be a lot of interest in a viable diesel bike. The Military diesel KLRs would sell to the public just fine, even at the higher price, if that company wasn't so busy selling to the military that they decided not to bother with public sales.

Even better, a turbo-diesel bike so you could get out of your own way when need be. I'd love a hybrid diesel/electric bike with in wheel motors and a diesel gen-set to power the electrics.

None of those things will see the market any time soon though, so it's a lot easier to just add more gas to extend your range. Depending on where you like to ride, or what your hobby is, this is a easy and common solution.