Aux fuel to vent line test

[The Beast]

This afternoon I hooked up a 2 gallon fuel tank to my vent line to see if it would feed properly. So far so good. Unfortunately I used vacuum line inside the fuel tank as a pickup tube and it doesn't seem to like fuel very well...it shrivelled up causing my test to end slightly early.

While the pickup line was in the fuel, it fed from the tank just fine and my main tank stayed nice and full. Tomorrow I'll rework the pickup line using fuel hose and try to get everything working properly. If this works out, as I am now more than confident that it will, I will install two, two gallon tanks as saddle bags.

Right now I have 7.2 gallons total fuel on board (5.2 in the main tank and 2 in the aux). This should yield 240 miles to the reserve light at 40 mpg. If this works out, as I am now extremely confident that it will, I will install a second 2 gallon tank and have them mounted as "saddle-bags". This will give me 9.2 gallons total fuel on board and should yield 320 miles to the reserve light.

This whole project cost 25 bucks and you can open any fuel tank at any time without having an overflow. No valves, pumps, or hassles...Of course right now the hassle is that I have a red, 2-gallon can bungeed to my rear seat! It'll take a bit more money to make a mount for the two cans, but overall this should be the best way to add fuel to the bike that I can think of.

Will post more after some refining and testing.

[Todd2]

Beast,

I'm VERY interested in this set up (aux, drain to main vent). I was wondering if this would work, but was concerned it would leak fuel out of the main tank cap. However, I'm surprised that no fuel will run out of the main tank when the main tank cap is open. Why wouldn't it gravity feed from the aux. tank into the open main tank, until the aux. emptied (overflowing the main)? Your gas can was vented - right?

In any event, I'm willing to try it with the Tourtank I already have installed. I can just disconnect my aux tank line from the return FI line and plumb it up to the main tank's vent tube (its a small tube, as I recall). I should be able to draw gas past my aux. fuel pump to check out how it works without much re-plumbing of anything yet.

Please let us know how your set-up works. THANKS!

Let's see....
Work on truck A/C.
Work on G/F's bike.
Work on House.
Ride.
Go to BB Rally
Go on cruise.
Work on VTX.
Maybe sometime in June.
decisions, decisions....... :wink:

Todd

[The Beast]

The key is not to feed from the "drain," but rather to feed from the top of the tank with a suction tube. Then you can open any cap at any time and will have no overflow problems. Am continuing the work today and will update this evening. The vent for the aux tank becomes the entire system's vent.

Beast out...for now.

[Todd2]

Beast,

Let us know how it goes. I'm still a bit confused: If the aux. tank sits higher than your main tank then your supply hose should just siphon gas out of your can with the main tank open (no real difference than taking gas from the bottom drain line of the aux tank). Oh well. I hope your testing works out favorably. Thanks!

Todd

[The Beast]

Todd2,

Come to think of it, you're right about the siphoning effect and you should be able to hook up to the drain with no problems. With that said, I haven't noticed any siphoning from my setup yet, but I think it is because the tanks are so close to the same height. Also, with the small vent line, it would probably take quite a while with the main tank open before it started to overflow.

I didn't have as much time to test mine on the road as I had hoped and am out of town for a couple of days now. Here's what I've done since my last post:

I replaced the vacuum hose pickup line with a copper tube that runs down into the tank. This solved the problem of the line coming out of the fuel. Unfortunately both of my tanks were slightly below full from the last test and I was short on time so just took off with them at the levels they were at.

Fuel feeds from the aux tank just fine, but at least with the main tank not full to begin with, it doesn't seem to suck the fuel out of the aux tank immediately. It seems to need to draw the main tank down a bit to create a low pressure, then the aux feeds. I rode 80 miles and the aux tank still has about 1/4 to 1/2 gallon in it. I would have assumed that the 80 miles would pretty much suck the aux dry since it's only 2 gallons...perhaps I was getting better mileage due to driving slowly!

In any event, the system does work and I am looking forward to adding a second tank and mounting them both as "saddle bags." I should never complain about fuel range again. Might even get one of those nice looking Tour Tanks sometime and plumb it up as you suggest from the drain to the vent. For now, I kinda like the look of my red 2 gallon can bungied to the back seat! :lol:

[The Beast]

Well, after a bit more testing I can most assuredly say that this mod is the easiest way by far to extend your fuel range. Works great and with both tanks full it feeds like it should (probably did with them not full, but I was opening the tanks so often to check things I broke the suction).

Went 235 miles to the low fuel light yesterday. When I filled up, I put 1.7 in the aux tank and 4.05 in the main. Came out to right at 40 mpg by the time I fueled up. Not getting the full 2 gallons in the aux due to having to fill it with the bike on the sidestand. I fill the main sitting on the bike.

Next plan is to order some nylon saddlebags and put a 2 gallon can in each one. Two of these suckers will have me right where I want to be with a 300 plus mile range. Now I just need time to get on with the SS1000. I suppose the anticipation is half the fun, though!

[The Beast]

Finally got a set of 36 dollar nylon saddlebags and have installed a 2 gallon can in each bag. Ran the feed hoses to a "T" under the seat, then to the vent line under the tank. Now I've got 9.2 gallons instead of the original 5.2 gallons. Should be about 340 miles or so to the reserve light now (at 43 mpg).

Also, since the bags are below the main tank there should be no siphoning issues at all. Can't wait to start trying them out.

The nylon bags match the nylon Tourmaster bag that I've got sitting on the passenger seat so the install looks pretty good. I'd like to install some quick disconnects on the fuel lines so I can remove the saddlebags without taking off the seat, but I'll get around to that later. Right now I'm going to enjoy having more fuel range than my car or truck!

[Todd2]

Sounds like you're getting it all worked out. Let us know how well it operates on your SS1000. I bought all the parts I need (quick disconnects) to hook mine up to my vent line, but haven't had the time, or inclination, to work on it, yet. If your set up works well, maybe that'll be incentive for me to work on my VTX again (instead of the little KLRs). Good luck.

Todd

[The Beast]

Since my last post I used the saddlebag mounted tanks a bit but kept having problems with them leaking. Admittedly the fittings were rather crude...so the latest, greatest, tested, and working solution was to use a tank for a boat and mount it back on the rear seat. Here are some pictures of the final version:

http://bigbikeriders.com/photopost/data/503/5782DSCF0939.jpg

http://bigbikeriders.com/photopost/data/503/5782DSCF0938.jpg

http://bigbikeriders.com/photopost/data/503/5782DSCF0943.jpg

The tank and fittings came from Bass Pro Shops. Tank was 24 bucks and the fittings were an additional 7 bucks or so... Quick disconnect fittings seal both the hose and the tank when disconnected. I painted the tank black with truck bed liner paint from Auto Zone. Also notice that the tank has a built in fuel gauge!

http://bigbikeriders.com/photopost/data/503/5782DSCF0940.jpg

The hose from the tank runs under the seat...

http://bigbikeriders.com/photopost/data/503/5782DSCF0941.jpg

And finally to a "T" fitting with a simple 5 dollar valve to switch between venting through the tank or venting with the stock vent system.

http://bigbikeriders.com/photopost/data/503/5782DSCF0942-med.jpg

To remove the tank you simply disconnect the quick-disconnect boat fitting and un-bungee the tank from the back seat. Then flip the valve under the seat to allow the stock vent to work again...just can't forget this step since with the tank disconnected the quick disconnect seals the hose which was your vent and you need the stock vent back in the system or bad things might happen!

Total cost was less than 50 bucks, not counting the previous attempts using other tanks. I'm happy with the results however and it seems to work fine. Still a bit slow to pull the fuel in from the aux tank, but it does transfer just fine.

[2002VTX]

From Bass Pro Shops, which tank did you use? The Moeller or the Tempo?

3 gallon, correct?

[The Beast]

It was the 3 gallon Tempo.

[2002VTX]

It was the 3 gallon Tempo.

Doesnt' the Tempo have some sort of reserve system per the website that could limit your fuel usage?



Per the website: Ultra Tanks have ... When the gauge registers empty, simply tilt the tank, and the reserve fuel supply becomes available.
Sturdy construction
Reserve fuel area...

[The Beast]

I hadn't noticed that before, but after looking at the tank I can see how that would work in the boat application. Interesting.

[ldrjim]

Heya, The Beast. I've been really impressed with all the research that you've done and your approach to adding aux fuel looks great.

I'm concerned, however that you're using bungee cords to secure the aux fuel cell. That seems like a potential problem should, God forbid, you're bike get in an accident.

Have you considered a more secure mounting system?

Jim

[The Beast]

Thanks ldrjim.

I've got the tank off right now since I've just been going around locally and have needed the back seat for my son to ride on. I pick him up from school a lot of times. I suppose that's the main reason for the bungee cord installation...quickly removable and very secure when installed.

My bike is used more like a pickup truck... I need the bungee cords to hold stuff on it. Going to and from work I routinely have the saddlebags and rear carrier bag that are in the pictures, then I add a roll-aboard and magazine case both bungeed to the rear seat. That's a lot of luggage and it won't all fit with the gas tank on it.

Next time I put the tank back on I'm going to increase the size of the hose going to the vent in order to try and speed up the draw a bit. We'll see how it works out. Last time I used the system it worked beautifully but was a bit slow to draw.

[billshep2]

Hey Beast,
You haven't posted since last april so I hope you are still around. I have been reading your posts on the aux. fuel tank to the vent system with great interest. On your last post you said you were going to install a larger vent line to see if the fuel would draw faster. Did you? And did it? I'm planning a BBG3000 this coming april and the extra fuel capacity would make all the difference in the world. The outboard boat motor gas can seems to be the ticket. Please post again if you are still into this. I would appreciate any more info. you might have. Thanks, Bill

[hilf]

Ditto. I'm planning a BBG in April. Several fewer stops will make a big difference. I like the simplicity of your design. Please update us.