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Discussion Starter #1
I am in need of adding an auxiliary fuel tank to my 08' GT. I do not want to reinvent the wheel if possible so I am looking for any and all tips on how to hook the aux tank into the main tank.

Any advice/wisdom out there? :dunno:


Thanks!!
DAve
 

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Have you looked into the solutions that they use for the GS? Guess that's the route I would take.

BTW, what for? Where you going with it that there isn't gas for 200 miles? :confused:
 

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Discussion Starter #3
I have looked at the GS solutions and have decided on a custom tank that will be mounted where the pillion seat is that adds right at 4 gallons.

200+ miles is usually enough, but I have a rally coming up that is multi day and I need to be able to go further than 200+ miles if needed. It cuts down on time off the bike and if your out in BFE in the middle of the night and need gas it sure is nice to be able to not have to worry about it as much!


Dave
 

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Which rally are you running, Dave?

Usually a proper bulkhead fitting works best. You can see one GT example below. Personally, I'd avoid drilling into the plastic tank if possible. On the LT, we would either plumb into the return fuel hose with a T fitting or put the bulkhead fitting into the steel plate that mounts the fuel pump assembly. I like the plate option, as it means you could just replace that part if needed rather than replacing the whole fuel tank. But I haven't pulled the GT tank off yet to see if there is a similar plate under there somewhere.

 

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Meese said:
But I haven't pulled the GT tank off yet to see if there is a similar plate under there somewhere.
Good and bad news. There is, but it's at the front of the tank. You could easily T into a line up there (good news, bad news, good news) and run it to the back of the bike.

I know this might shock you, but the quick disconnect is flimsy. Real flimsy. Cheaper than the LT's. I foresee a lot of breakage as these bikes age and the plastic becomes brittle.

The quick disonnect is the same size as the LT (I broke mine on the GT and scabbed a leftover LT one on it till I got a replacement) but it has a 90 degree turn to it.

Mayhaps we should start looking for the brass and make some preemptive strikes.

Man, I like working on this bike more than the LT as far as stripping it past the gas tank and airbox. Tons easier. I'm just waiting for one of us to grow some balls and go further.
 

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I've used those brass QD fittings on my work machines for many years. They do make 90 degree versions as well, so it's just a matter of finding the right part number.

As far as stripping the bike down and creating our own work procedures, I've been thinking about that. My GT is now officially out of warranty at 41K miles, and I have a valve check needed soon. :)
 

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Discussion Starter #8 (Edited)
[I said:
Meese]Which rally are you running, Dave?[/I]

A couple of different ones this year, The CAL24 and the Spank Rally. Really need the tank for the Spank Rally. Not having to stop as often is a real bonus as you know.

Thanks for the tips, I am going to take the tank off this weekend and have a look to see what is what under there.

Dave
 

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OK, where did you actually plumb your aux fuel into your GT?

I have searched all over this and other K bike boards for aux fuel info. I see above the photo Meese shows with the bulkhead fitting into the plastic. Ken, you mention the possibility of plumbing it into the metal plate elsewhere.
1. Where?
2. What did YOU actually do?
3. What advice would you be willing to provide me to do aux fuel on my 09 GT?

Thanks!!!
 

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That pic is from a friend's bike, before I added my aux tank. I put my bulkhead fitting in a similar location, but lower and more centered (down between the two seat rubber bumpers).

I pulled the gas tank and looked at the metal plate, but it's pretty crowded down there, with no flat area that I could easily drill into. So I went into the tank itself at the back. As long as you make sure there are no interference problems with the fitting or hose and also use the correct plastic sealing washers, it'll be fine. Oh, and do drill the gas tank hole with a proper step bit. That's the easiest way to ensure a clean hole that will seal well. To drill the hole, mark it carefully then drill a pilot hole from the outside before switching to the step bit. Obviously the tank should be empty, and you can remove the metal plate to get your hand up in there with a cup behind the hole. That will catch most of the plastic shavings before they get sent all over the inside of your fuel tank. Then you can get a socket in there to tighten the fitting up properly.

Other than that, you have to decide what type/size of fuel call and where to mount it. I used a Jaz 5-gallon fuel cell from Summit Racing. That was the best combination of size, shape, and price. I mounted it in place of the passenger seat using some custom brackets that kept it low enough that my 49L case would still open. I made the straps to go around the fuel cell as well, although I'd recommend just buying the pre-made ones that Summit offers.

Do get the foam inserts which minimize fuel sloshing while leaned over in a corner. Also, you can use the same quick disconnects that BMW uses for the main fuel line, but get them in chrome-plated brass instead of plastic. And while you're at it, replace the crappy plastic connectors that BMW puts on the fuel tank with the metal ones as well.

I used an inline ball valve to isolate the fuel cell from the main tank. Ride until the light comes on, reach behind and flip the lever, wait about 20 minutes, then you have a full tank again. It does take a long time to drain the entire 5 gallons into the main tank, but at that point you're just riding so it's no real bother. And it's pretty cool seeing the fuel level rise as you're riding along. :)

I also made up a simple back rest out of some dense foam and vinyl covering. And I added two 3-liter water bottles as well. Add the small bag attached to my handlebars that contains granola bars and other munchies, and I can easily ride out the entire 11.3 gallons.

With my ~40 mpg average, I can get about 450 miles between fill ups. You could easily get over 500 miles if you ride a bit more leisurely, but where's the fun in that?

 

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Meese,
A couple of questions. With water and gas what do you figure added weight is up top. Do you notice it when everything is full? What did you do about the space underneath the tank where the passenger seat use to be? Is it covered to keep out the elements. Is your application a permanent mount? TIA
 

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swmckinley54 said:
Meese,
A couple of questions. With water and gas what do you figure added weight is up top. Do you notice it when everything is full? What did you do about the space underneath the tank where the passenger seat use to be? Is it covered to keep out the elements. Is your application a permanent mount? TIA
The overall answer is that even with full fuel and water, one saddlebag full of tools, and the other full of clothes and a laptop, it's still less weight than a passenger.

Gasoline is roughly 6 lbs/gallon, so that's 30 lbs plus the weight of the container and brackets. Water is a bit over 8 lbs/gallon, so my two 3 liter jugs add another 13 lbs. So figure about 50 lbs added where a passenger would normally sit, plus about that again sitting lower down in the saddlebags.

Yes, you do notice the weight, but it's really not that bad. Remember, the bike is set up for doing serious distance rather than track days, although I can still strafe corners with the best of them. It just means that I have my choice of several states to choose from when searching out the twisty roads. :)

I did add the foam insert into the fuel cell to minimize sloshing from a half-empty tank, which can be disconcerting when in the middle of a tight, fast corner. Ever had a passenger squirming around on you?

I looked at several mounting options, and decided to remove the passenger seat entirely. I thought about mounting the fuel cell to a spare passenger seat that was cut up, but the seat pans are plastic plus that would have made the whole package sit higher. This way, I get a solid mount and the cell sits lower so that I can still open my trunk fully. Plus a few yards of metal stock was cheaper than another passenger seat.

To cover up the under-seat electronics, I simply got a yard of vinyl from a local fabric store and cut out a rough cover. I laid it over the mounting brackets, then tucked the edges in around the silver side panels. The tank mounts above this vinyl panel. This kept everything dry through some serious rain all the way from Toronto to Boston. I used the left-over vinyl and an old camp sleeping pad to make a simple back rest.

I made it all removable since my wife still rides with me, although not on the crazy IronButt rides. :) I can remove/replace the whole setup in about 20 minutes. I also didn't make any permanent modifications to the bike, except for the gas tank inlet hole which can be easily plugged.

Overall, I'm quite pleased with the project, especially since I threw it together in a couple of long days at my friend's shop. If I redid it, I might use the passenger seat mounts instead of bolting everything down to the frame, but that would just mean it was simpler to take off and replace.

It did take me a while to get used to the 450-mile range though. For the first few tanks, my body was expecting to stop at about 250 miles and I had to retrain myself to stay comfortable in the saddle for another 3 hours longer. :)
 
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