gasoline camel

[thr3shold]

I was thinking the other day of adding an auxilliary gas tank under neath the seat area and where the stock air box used to be on my '80GS1100E to extend my range. The area is worth for 2-3 gallons I figure. Has anyone tried to do this or come up with some other arrangement to fit more gas on their bike?

[Jeff Tate]

My first thought is that you'd need a fuel pump since the aux tank would be so low.

[HiSPL]

Check out some rally bikes. They do this all the time with gas in their saddlebags, under the seat, and beside the tank.... I'm sure they have come up with some fancy solutions.....

[Anonymous]

Yea, it's a little low so you will have to remove it and dump into your tank or get a fuel pump.

You must have an iron butt. I like to stop every 100 miles or so just to stretch and walk a bit. Filling up is a great excuse to do that.

My last trip to eastern South Dakota was 900 miles - through the Black Hills - very nice ride. I rode through Wyoming and S.D. at over 100 mph most of the way. Only saw 2 cops! Anyway, after about 1.5 hrs in the saddle I was ready to take a break.

[saaz]

On my old GT750 I had an extended petrol tank custom made up ny someone who used to own an outfit. It was extended at the top. The downside is a more top heavy feel. I needed the range to get over a minimum distance of 350kms at night before petrol staions were open 24 hours.

My Gs1000 will do 400kms at normal higway speeds, which is plenty enough these days.

[Anonymous]

I just read my earlier post again. On the fuel pump issue - you can't use a fuel pump fed directly to the carbs as the float needles are designed to operate on gravity fed fuel. This would be too much pressure for the little buggers. You would have to pump fuel to the tank and then let it take it's normal course.

Kind of a pain in the butt. Just thought I'd clarify that a bit.

[thr3shold]

my original thought was to mount the tank under the seat and move the petcock as low as possible but still be above the carbs, then weld a largish bung to the gas tank and route a feeder hose to the one underneath my seat, then from the underseat tank to the petcock.(plugging off the other hose from the main tank) I could make it possible to undo the hose routing if I needed the under seat space for something.

[terry]

I think Swanny is on the money regarding the need for a fuel pump from the lower tank to the main tank, a pretty low pressure unit would be most suitable so that it doesn't pressurise the fuel in the main tank and force it out through the filler cap vent, then over you and the engine.

I'm no expert on fuel pumps, but I had a BMW K100RT a few years ago, it's fuel injected so maybe the fuel pressure would be too high, but if not, it did have a neat little pump inside the fuel tank, which you could remove by first taking off the whole fuel filler cap and surround assembly. If you could locate a complete damaged K100 tank, (ebay?) you could probably make good use of the pump, fuel filter and filler assembly, then all you'd need to fabricate would be a basic steel or alloy tank. :twisted:

[Anonymous]

what about a fuel pressure regulator??? how low can you make the pressure on one of those. i know the standard fuel pressure is about 7 pounds or so on a fi motor (if ive remembered right from all my reading) but i believe that is on a car, not sure if it is the same on a bike the BMW.

[Anonymous]

just had another thought, why not just put a toggle switch to only switch on the fuel pump when you want to turn it on after riding for 100 miles or so you should be alright then not to over flow the tank. Just make sure that you do not run the pump dry for very long because it is very hard on them.

( I might have to think about doing this to my bike, like i say "you can't ever have to much fuel")

[Anonymous]

auxilary gas tank

I fabricated a tank for my 82 Katana that sat in place of the rear fender and seat. The bottom of the tank was about 2 inches lower than the top of the frame rails. It fed through to the carbs no problem once I rerouted the carb fuel line to behind the carb. I attached a T and a petcock to the line from the aux. tank. 12 liters and a range of over 350 miles. Too far for anyone to sit on for that long!
I kept the aux tank petcock closed till the main tank ran onto reserve, then opened the aux petcock. then finally opened the reserve tank. worked great.

Ger... gammas and katanas

[Gerry]

The V-Max has a tank under the seat with a fuel pump, maybe this set up would work for you,

Gerry

[argonsagas]

If any fuel is stored at a level lower than the original fuel tank, a pump will be needed, The fuel pump will deliver the fuel to the main tank, from which the normal gravity feed will work as usual.

The distance you can manage depends on your speed and total fuel capacity. My 1100GK carries 22 litres, and will run to 300 kms at low speeds, but uses considerably more at high speeds.

As for comfort, the seat you use makes a world of difference on long distance riding.

I just completed a 3500 mile trip (700 miles a day for four days) on my 1100GK, and had no tail end problem at all.

[dpep]

I am considering a lower tech approach to increasing my range on long trips. It is to simply carry a gallon of gas in an approved container securely lashed somewhere on the bike. I would then be able to extend the number of miles I go after switching onto reserve without the risk of getting stranded roadside.

Has anyone else ever tried this approach? What would be the safest location for carrying the additional fuel?

[Anonymous]

I'm not the most mechanically minded person in the world so forgive me if this suggestion is pants

Could you perhaps mount your tank under the seat with a pump that goes to the main tank with a valve/switch that on activated the pump when the fuel was below a certain level