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Discussion Starter · #1 ·
I've been working on setting up a Aux fuel cell for them Hexheads. This project has come and gone a few times over the last 2 years but was rekindled on another site.

This time I mocked up a 1 gallon can with a custom fuel plate to run a vacuum setup.

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1-gallon can all set up with a tank vent off my long gone DR650

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Lashed to the rear rack with a ROX strap and ran directly to the tank vent barbed fitting on the sucking jet plate.

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Went out for a 20-mile run. The bike had about 1/4 tank when I started. When I got home the Aux fuel cell was 3/4's empty and the fuel counter on the GS was starting to increase.... SUCESS!

I'm going to run this a few more cycles then if all checks out moving to a 3-gallon boat gas tank to give that a whirl.
 

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Wouldn't it be much easier to stop at a gas station and fill the tank ? The looks of that set up are a bit primitive for such a sophisticated bike imo.....
 

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Discussion Starter · #4 ·
Wouldn't it be much easier to stop at a gas station and fill the tank ? The looks of that set up are a bit primitive for such a sophisticated bike imo.....
It would be easier to drive a car with a 500-mile fuel range. But it's not ease I'm after I want and extended range fuel range.

When a buddy and I put in bid days he has to stop ever 200 on his K-bike. Since I cannot double his mileage, I end up topping up too with only a couple gallons. I'd rather fill up every other time. This way I use my CC less it also gives me the opportunity to hit the bathroom 1st and have a few extra minutes to stretch, grab a snack and a swig if water. When doing big days there is no fooling around taking 20 or 30 minutes at every fuel stop.

My biggest day was 1144 miles that about 29 gallons of fuel. With the GSA tank + 3 gallons that's means if I start out the day with a full complement of fuel, I only have to top up twice whereas my buddy has to 6 or 7 times.

This setup is a but crude, but I decided to use stuff I already had on hand to verify it would work. So far, I have $15 wrapped up into this setup and preliminary test are positive. The next setup will be cleaner but ultimately as long as I can carry extra fuel and easily be able to move the tank amongst the bikes that is where my priorities are. Looks are secondary.
 

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Discussion Starter · #5 ·
Little more fiddling around today and found a 3-gallon tank that had dimensions that worked for what I wanted.

1- Attwood 3-gallon tank - $52
1 - Section of 1/4" fuel line - $7
2 - 1/4" quick connects - Free had in the toolbox
1 - 1/4" barb my IPS adapter - $4
2 - Rox straps - $14
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Total $77 for an extra 120 to 140 miles of range (y)

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Discussion Starter · #6 ·
After a couple cans of thinking juice last evening, I reoriented the aux tank and flipped it 180 degrees. This put the filler on the high side and just generally fit the bike better. Wen tot eh gas station this morning and loaded 3.25 gallons in the aux tank fuel counter sat 70 miles to empty and started riding. Rode a little over 230 miles and the fuel counter was up and down biut when I parked it was at 71 miles to empty. Fuel level dropped about 5/8". After a little while I notice the tank was bloating. I guess the heat from the engine was warming the main fuel tank and pushing pressure to the slave tank that had 5lb relief. So out came the drill and a 1/32 hole in the center and now it will be atmospheric. After i warmed up when for another 30 miles and now at 88 miles to empty and the aux tank has transferred about 1/3rd of its capacity.

Next i'll build a dedicated cradle for the fuel cell that clips in place of the pillion seat. I have some design ideas bouncing around in my head but will think it over a few beers this afternoon.

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Tank flipped to keep filler on the high side when on the side stand.

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After 20 miles the fuel consumption

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@PerazziMx14 I'm trying to wrap my head around how the fuel is transferring. You mentioned "directly to the tank vent barbed fitting on the sucking jet plate"...so is it simply siphoning into the tank as the fuel level drops?

I wouldn't think the tank would have enough suction to draw the fuel over. But...I didn't do so well in physics lol.
 

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Discussion Starter · #8 ·
This of it more like a low- and high-pressure system. Sitting static, both tanks atmospheric and have the same amount of pressure pushing down on them. Once the bike is started the main tank since fuel is being sucked out and injected to the engine it becomes a lower pressure tank. The high-pressure tank wants to push into the low-pressure tank until they equalize. Lift (elevation difference of the two tanks) and siphon both occur because of the pull push created by the pressure differential. It's also why the high-pressure tank will not continue to siphon into the low-pressure tank once the motor is shut off or the fuel cap on the low-pressure tank is opened as the pressures equalize and since there is no more pull/push fuel flow stops. Once the slave tank is exhausted and there is no more fuel in the hose the vacuum will break and both tanks will again equal and be atmospheric.

It is so simplistic but works so well I'm not sure why people fool with pumps and bottom outlet salve tanks, It just over complicates a underly complicated system.

Redline is the fuel line from the salve tank to the sucking jet/tank vent plate. Red dot is approximately y where the tank bent is. In the example on the test tank, we need about 5" of life to get the fuel flowing. Then new tank since it sits lower and the fuel supply is not as high needs even less lift.

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NIce setup, just one problem, it is messing with the evap system (modern bikes and cars have closed fuel system, the fuel can not evaporate in the atmosphere, excessive vapors are stored in the charcoal canister and burned later in the motor).

That will not pass emission test in some states, could probably get you fined here in Quebec (Canada).

To keep your system closed, add a check valve allowing only air to enter the aux. tank and you'll be good.
 

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Discussion Starter · #11 · (Edited)
NIce setup, just one problem, it is messing with the evap system (modern bikes and cars have closed fuel system, the fuel can not evaporate in the atmosphere, excessive vapors are stored in the charcoal canister and burned later in the motor).

That will not pass emission test in some states, could probably get you fined here in Quebec (Canada).

To keep your system closed, add a check valve allowing only air to enter the aux. tank and you'll be good.
No emissions testing in Pennsylvania on motorcycles. In fact the county I live in doesn't do emissions testing for automobiles.

Even if we had emissions testing it would be easy enough IF I kept the charcoal canister in place to simply detach the aux fuel cell reconnect the hose from the overflow to the charcoal canister and be in compliance for the emissions testing.

Adding a check valve does the same thing the CARB compliant auxiliary tank lid would do. It would allow pressure to build in the system as the fuel expanded. That is what I am avoiding by letting the system inhale as well as exhale.
 

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Sorry to say guys, this whatever you want to call it looks like a suicide waiting to happen.......
 

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Discussion Starter · #13 ·
Sorry to say guys, this whatever you want to call it looks like a suicide waiting to happen.......
What's your stance on Rotopax or fuel bottles or bladders?







What is really interesting is most people are put off by this set up but are completely content with strapping stand alone fuel container to their motorcycles. Why is it when you connect the aux and main tank with a 1/4" hose its a ticking time bomb. Does the 1/4" hose make that much difference? If you think about it the main tank is plastic and it houses electrical component that are swimming in flammable gasoline. Then you wrap you legs around it as it sits atop a hot engine and exhaust that have many whirling and twirling parts. It this really any safer than a plastic fuel tank on the rear of a bike?

I get it if you are not comfortable with this setup do not use it. But do not criticize the safety of it when you have a far worse potential for something bad to happening sitting right between you legs.

We all know motorcycling is the safest thing we'll ever do😨
 

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What's your stance on Rotopax or fuel bottles or bladders?

"potential for something bad to happening sitting right between you legs. "

A GS Adventure's 8 US gallon tank and more than ½ a brain cell between the ears. What you have between your legs would be akin to an BBQ'd 🦐 prawn when that contraptions goes up in flames wouldn't you say? :eek::ROFLMAO::ROFLMAO:
 

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Discussion Starter · #15 ·
Again why is this "contraption" any more at risk than the 20L or 33L gas cell setting between my legs? They are both plastic. They are both connected to the same motorcycle. They both have fuel in them and only one of them has electrical components in it.
 

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Well it is red... there is that.

We all can imagine horrible out comes for just about everything we do. That tank exploding is possible, but not likely. Might come off and spread fuel in a very violent wreck, and then your loved ones could not have an open casket funeral.
 

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Discussion Starter · #17 · (Edited)
So again I ask about you thoughts on Rotopax, fuel cans and/or bladders? They like the onboard fuel tank can all fail in an accident but people haphazardly strap, lash tie then to their bikes panniers, top cases frames like a worry free badge of honor.
 

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So again I ask about you thoughts on Rotopax, fuel cans and/or bladders? They like the onboard fuel tank can all fail in an accident.
Indeed, all certified anything can fail, even standard tanks on a GSA for example. However, they have undergone rigorous and extensive independent testing. This is a field in which I have some expertise. Having seen fuel tanks punctured, as would or could be expected in a collision or off road excursion for example, then igniting is an utterly shocking sight.

And it's not just your neck that's at stake my friend. Stay safe and well.
 

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Discussion Starter · #19 ·
I've asked twice and still nothing from the naysayers.

An additional question: What are the chances in a collision the the rider and bike will stay together?
 
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