Tour Tank Setup

[davesax36]

Ok, guys. I've got my stuff all together and have put about 500 extra miles on in the last two weeks. Here's what let me do that with only three stops for gas.

I ordered an 8" aluminum fuel tank from http://www.coyotetanks.com/8inchendfillertanksusa.html

I did not get the "Tour Tank" one because it was about $40 more, and I decided that any sloshing around was probably going to happen whether there was a baffle in there or not since I got the smallest one available. I also ordered a locking gas cap and the hookup kit for 5/16" line.

It arrived in a little over a week. Everything was in one box, and they sent the original non-locking gas cap along with the tank, but with the locking one already on there. Somebody actually looked at my order to do this. That made me feel good.

The tank is raw aluminum, so it has a brushed feel to it. I like it. The circular brackets work just fine, but one of mine was twisted/bent a bit and was a real pain to get on, so it marred the surface in a couple places. Not a big deal to me since I bought it to hold gas, not win a beauty contest.

I have the Cycl-istic luggage rack, which is the perfect system for mounting one of these things. The rails on the rack are spaced just right for the brackets on the 8" tanks. I went to the hardware store and bought two black painted fence brackets, 4 8x1.25x25mm bolts, nylon lock nuts to match, and proceeded with the install. I drilled my own holes in the black plates, lined up the tank, and tightened the stuff down. Then I had to decide how to integrate the fuel lines and T-fitting.

I have the T-fitting oriented so it lines up with the line going back into the tank. If you look at the pic, it makes sense to me to have the path of least resistance going back into the tank rather than into the fuel filter. My goal was to open my flow valve somewhere around 100 miles to refill the stock tank rather than having it plumbed in downhill towards the fuel filter. I don't want to drive around with that reserve light on.

Also, the brackets for the Cycl-istic rack do not allow my corbin seat to seat fully onto the frame rails. This seems to be what has allowed me to run the fuel line the way I did. It would have to run under the grab rail and frame rail but over the fender for most guys, I think.

Once it was all hooked up, I went out for a shakedown ride. I went 203 miles on that ride without seeing the fuel light come on. I put in 4.5(ish) gallons. I think my speedo calibration might be a bit optimistic, but whatever. Google maps says it was 198 miles.

One thing you need to know is that once the fuel valve is open to drain the extra tank into the stock tank, it takes a couple minutes to fully drain. When it finishes, you will be greeted by the feeling that you've just run out of gas. No amount of fiddling with the reserve switch can make up for the lack of vacuum of a 2.5 gallon air pocket in the fuel path. All you really need to do is drive a couple miles with the valve open, then close it, to maintain vacuum, but it was not fun figuring this out with an 18-wheeler closing in behind me going down a hill.

I guess that's about it. It's nothing special, but it really gives me peace of mind knowing that I've got plenty of reserve fuel and can go longer between stops if I choose to.

 

[Biker Dash]

Excellent work! My only issue would be where the tour tank is placed. Gonna be fitting a trunk there.

I have seen auxiliary tanks that replace the air box cover. That would be better fitting for what I need.

 

[davesax36]

I was going to mount it about 8" further back so I could still fit my tail bag on with a passenger, but I wanted to get it on and running first. Plus, I added Fatmax saddlebags... Are you carrying a passenger? You could put your trunk on over half the rear seat and still fit one of these tanks. It's so little. My mom even called it cute...

 

[D-Max2012]

Nice Project.. I was always intrested in increasing distance of my max. Right now, I get about 99 miles before that red light come one.. Nice work you got there.
I was wondering about an automated way that you can run the reserve tank and have it flip to the stock tank, once depleted.. Or it that asking a bit much? :biglaugh:

Maybe a fuel cut over valve, but there is no sensor on the external tank, so once depleted, the bike would just cut off, without warning. Maybe a manual switch over valve? like this... Even this requires a conscious thought to switch over.



I wonder if there is something out there that could be triggered, when the low fuel light comes on, that would open a valve from the external tank, to let it drain into the stock tank while riding. That way, you would still have your warning system in place.

 

[Miles Long]

Nice Project.. I was always intrested in increasing distance of my max. Right now, I get about 99 miles before that red light come one.. Nice work you got there.
I was wondering about an automated way that you can run the reserve tank and have it flip to the stock tank, once depleted.. Or it that asking a bit much? :biglaugh:

Maybe a fuel cut over valve, but there is no sensor on the external tank, so once depleted, the bike would just cut off, without warning. Maybe a manual switch over valve? like this... Even this requires a conscious thought to switch over.

View attachment 49438

I wonder if there is something out there that could be triggered, when the low fuel light comes on, that would open a valve from the external tank, to let it drain into the stock tank while riding. That way, you would still have your warning system in place.

Davesax - nice setup! Not sure what you mean about the vacuum problem - isn't the locking gas cap vented?
Dmax - IMO, the best/simplist auxiliary tank setup involves one that dumps directly into the stock tank.
This setup means you are only filling the aux tank when stopping for gas, and there is no need to flip the center seat section to get at the OEM cap - meaning you can leave any luggage on the passenger seat in place. The low fuel light functions as usual - you just get to go much further before seeing it!
To do this involves having a vented cap on the aux tank, an aux. tank outlet at least the diameter of the filler inlet, a filler hose of the same I.D. connected to the main tank filler pipe, and blocking off the OEM vent/tipover valve outlet.
All very "doable", using over-the-counter plumbing hoses, PVC elbows, and clamps.
Some alteration of the passenger seat, if still to be used , would be required.
Cheers!

 

[Redbone]

Having 200 miles between fill-ups is nice, your setup looks slick Dave! ! Thanks for the write-up and pictures.

 

[D-Max2012]

Dmax - IMO, the best/simplist auxiliary tank setup involves one that dumps directly into the stock tank.

That's a good idea, but, when you go to the pump, how long would it take to fill a 4 gallon stock tank that's being filled from an auxiliary tank. I would think you'd have a problem, simply because, the stock vent line is tiny. If the stock cap is sealed, and some type of fitting is leading from the aux tank is feeding it, it would take a tremendous amount of time to fill your bike.
Unless I'm messing something there..:bang head:

 

[davesax36]

Davesax - nice setup! Not sure what you mean about the vacuum problem - isn't the locking gas cap vented?
Dmax - IMO, the best/simplist auxiliary tank setup involves one that dumps directly into the stock tank.
This setup means you are only filling the aux tank when stopping for gas, and there is no need to flip the center seat section to get at the OEM cap - meaning you can leave any luggage on the passenger seat in place. The low fuel light functions as usual - you just get to go much further before seeing it!

Yeah, Miles. The cap is vented. The problem comes when the fuel pump tries to suck gas out of the stock tank and air out of the aux tank at the same time. There's not way it can pull that volume of air and the weight of fuel at the same time. It's because of the T-fitting and it's access to a huge empty space relative to a little piece of fuel line.

It takes a couple minutes for the 2+ gallons to empty into the stock tank from the aux tank, so doing it like that at the gas pump would take forever. I'd love to do that, but you'd need at least a 1" ID pipe to equal the flow rate of a gas pump, so I'm not ready to even think about that mess.


D-Max. You can get a tour tank with a gauge in it. I have a fuel level indicator on my guages now, so I could use that, but you have to get a bigger tank for them to put that little neck and guage on the tour tank. I wanted the smallest thing possible. Now that I have it, I think I would have been ok with a 10"x12" tank, which would have effectively doubled my fuel capacity. That would be a pretty silly range, though.

 

[Miles Long]

That's a good idea, but, when you go to the pump, how long would it take to fill a 4 gallon stock tank that's being filled from an auxiliary tank. I would think you'd have a problem, simply because, the stock vent line is tiny. If the stock cap is sealed, and some type of fitting is leading from the aux tank is feeding it, it would take a tremendous amount of time to fill your bike.
Unless I'm messing something there..:bang head:

The main purpose of the vent is to introduce air into the system, above the level of the fuel, while the bike is running. if you take a close gander at the stock vent setup, you will find a brass orifice plug in the vent tube of the tank, where the rubber tube connects. It is only about 1/32", if that. So it takes very little air for the system to work properly.
I have two aux tanks, a four liter and a six liter. They both dump directly into the main tank, via a 1 1/"2 hose (or whatever the O.D. of the filler pipe is).
When filling, I depress the nozzle at least to half of the flow capacity. Filling takes no time at all!
Cheers!

 

[D-Max2012]

They both dump directly into the main tank, via a 1 1/"2 hose (or whatever the O.D. of the filler pipe is).

.. So on your setup, you have a large hose leading from the bottom of your aux tank, into the main tank.. Much larger than 5/16"... If so, I can see how that would work and not take a long time to fill up, because the filler hose allows air to rush out, while fuel is rushing in.

When filling, I depress the nozzle at least to half of the flow capacity.

The stock tank O/D on the filler pipe is 2.0 inches. The fuel pump pipe is something like 3/4 inch. I now see how you are handling the speed of filling up and avoiding a potential mess, (not to mention fire). :biglaugh:

The OP, DaveSax, shows a regular diameter line leading from the aux tank to the main tank's pickup line, via a T fitting. So, unless he has an extra "LARGE" vent line leading out from the main tank someplace, that was not photographed, he would have to wait a LONG time for gravity to dump a 2 gallon aux tank into a 4 gallon main tank, that only has a 1MM vent line. Not to mention.. The main tank must be totally sealed off from the outside, or good old fluid dynamics would let gravity take over, and find an opening, since the aux tank is sitting higher than the main tank.

So, if there is no extra large vent tube coming from the main tank, (which also would have to be routed up slightly above the filler hole of the Aux Tank), I would think, I could fill up 6 or 7 stock V-Max's by the time one system it topped off, if the only vent is 1MM.

Also, the stock vent tube is tiny, about a 1MM opening. You must have some type of vent line to keep the pressure in the tank at 1 atmosphere. That's why it leads out to an open tube near the battery box..
You don't want your tank ballooning up on ya.
Ever put fuel in a fuel container that is 100% sealed? Gas fumes swells up terribly. I don't want to be sitting on something like that.. :biglaugh:

Either way, you're still getting more miles than me.. :clapping:.. Good job.

 

[Falaholic]

I was wondering about an automated way that you can run the reserve tank and have it flip to the stock tank, once depleted.. Or it that asking a bit much? :biglaugh:

http://www.wvodesigns.com/raw-power-3-port-2-way-solenoid-wvo-valve.html

 

[Falaholic]

To do this involves having a vented cap on the aux tank, an aux. tank outlet at least the diameter of the filler inlet, a filler hose of the same I.D. connected to the main tank filler pipe, and blocking off the OEM vent/tipover valve outlet.
All very "doable", using over-the-counter plumbing hoses, PVC elbows, and clamps.

Please more info on this.
My original thought was to drill into the main cap and run a line from the AUX tank to the main cap.

 

[davesax36]

Please more info on this.
My original thought was to drill into the main cap and run a line from the AUX tank to the main cap.

I'm pretty sure Miles doesn't really have a passenger seat. His tank setup is pretty serious, with a 2" pipe running from the stock filler neck into his "back seat tank" and another running to his "aux tank" if I remember right. It's like one huge tank made to look like a back seat and an aux tank.

The problem is that there is already a vent line in the stock tank. If you have a fuel source above that vent line, gravity will let it flow out of there (slowly, but it will) until the fuel level equalizes at the level of the vent pipe.

 

[Falaholic]

Yeah, Miles. The cap is vented. The problem comes when the fuel pump tries to suck gas out of the stock tank and air out of the aux tank at the same time. There's not way it can pull that volume of air and the weight of fuel at the same time. It's because of the T-fitting and it's access to a huge empty space relative to a little piece of fuel line.

Please excuse me, but I can't seem to wrap my head around this. If the cap is vented, then the air pressure inside the main tank is always nominal. Is it because the sudden amount of AUX fuel going into the main tank, and the main cap can't vent the residual pressure?

 

[davesax36]

No. The way I think of it is this. The fuel pump is sucking fuel up and out of the tank, It's usually a closed system since there is fuel in the lines for it to suck on. When the fuel from the aux tank has finished emptying into the main tank, there is a fuel line and a tank full of air that it now available for the pump to suck on. It will not suck fuel up the pipe from the stock tank when all that air is available. That's why I have to shut off the aux fuel line after a couple minutes. If the aux tank was not vented, the tank wouldn't drain into the stock tank properly.

You can do the experiment at home by cutting a hole in the side of a straw and trying to drink through it.

If the fuel pump was PUMPING fuel up and out of the tank, there would be no issue. Since it is SUCKING fuel up out of the tank, that extra line running to a vented volume of air eliminates the vacuum needed for the pump to get the fuel out of the stock tank.

That's the only way I can think of it, since I even forgot to close the valve today on the way to the gas station to start out my ride. I lurched to a halt right at the gas station, and couldn't figure out what I'd messed up until I looked back and saw the little red knob twisted to ON. When I switched it OFF (sealed line) the bike fired right up again so I could continue.

 

[Falaholic]

Someone help me out here.
Which line is the vent, main fuel line, and overflow.
Schematic fuel

 

[davesax36]

14 connects the main fuel pipe to the filter, then on to the pump.
28 is the vent to the tip-over valve.
23/24 is for overflow/spillage out the cap

I cut 14 to insert my T-fitting because it's where the fuel comes out of the tank and does a U-turn towards the filter. My whole setup is sitting on top of the vent/tip-over line in my pics. It has a little tab that folds over to hold it in place.

 

[Falaholic]

If the fuel pump was PUMPING fuel up and out of the tank, there would be no issue. Since it is SUCKING fuel up out of the tank, that extra line running to a vented volume of air eliminates the vacuum needed for the pump to get the fuel out of the stock tank.

I'm confused trying to wrap my head around the dilemma . Perhaps I'm placing my own variables into the equation.

If your draining the AUX into the main taink, you will need to plug the main tank's vent tube, and just have the AUX vented cap do the work? Is this correct and will it work?

 

[davesax36]

No. I wait to drain the aux tank until the main tank level is low enough to handle the volume added from the aux tank.

UNLESS you want the aux tank line to be open all the time. Even then, you'd have to have to make sure the stock cap was sealed.

 

[Falaholic]

14 connects the main fuel pipe to the filter, then on to the pump.
28 is the vent to the tip-over valve.
23/24 is for overflow/spillage out the cap

Ah, thank you.
If you know, can you please explain how the tip over works, with there being a canister, and two (42/34) lines?