'81 GS650 GL Fuel Tank

[Guest]

(First time post here) I tried searching but the site blows up with a memory issue, so I am sorry if I am posting a question that may already have an answer.

I have an '81 GS650GL that I bought 18 months ago, it has 12,500 miles on it and is in great shape. Both my wife (sitting on the bike in my avatar) and I love riding it. The problem I have is the fuel tank is too small. It holds about 2.4 gallons or so and doesn't last long on long drives. We get about 45 miles a gallon with two riders so I guess that's good, but I need to hold more fuel for longer rides so we don't get stuck with no stations around. Does anyone know if there is another larger capacity tank available or what other model tank will fit and offer more capacity?

TIA

[tom203]

With this bike, you got to find gas stations every 100 miles- yeah, its annoying. Actually the tank holds 3.2 gallons, BUT the stock petcock leaves 1 gallon in reserve, so that's why it looks like about 2.4 gallons. The G and E model has 4.2 gallon tank, but it's bigger at back and mounts differently.

[Steve]

My son's '82 650L has the same tank (more or less), I think it holds 3.4 gallons, but Tom could be correct at 3.2. It usually hits REServe at about 110-120 miles.

I have not yet tried to fit my wife's 850L tank on it, but should try it some time. Starting in '82, the 850L got a 4.5 gallon tank, where previously it was the same 3.2 or 3.4 as the 650.

.

[Doughboy]

Thank you both for your replies. It is annoying at times when we want to go on back road rides. One ride last year almost made us walk, thanks to gps and a smartphone we found a station in time.

Steve, if you get the time, can you check the tanks for similar measurements to see if it may fit. I have a vintage bike parts location 10 minutes away and he may have a tank I can buy if it does fit.

[Wingsconsin]

An option

It looks like you have a trunk mounted on the rear -- maybe on a rack of some sorts..? If so ...then you can mount an Auxiliary Fuel tank back there and run the fuel line towards the carbs. By adding just a small tank you can add another 3.5 gallons of onboard fuel, be below the rack weight limit, and extend your range by nearly double..

Here is a picture of what we did to my Sons CX500 Custom in 2012. His tank held 2.2 gallons and even at 55 MPG the range was only just over 110 miles... We went to Tennessee that year and he wanted a longer range..an additions 3.5 gallons added another 160+ miles to his range...

You can see the tank on the rack in this photo.
running the fuel line is easy -- put a manual petcock near the tank (by the riders hip for easy switching) and a "T" fitting in line on the fuel line below the petcock on the tank but before the carbs. Gravity feeds the fuel into the carbs just like ti was coming out of the regular tank.

What we did was use the OEM tank as the MAIN (2.2 gallons) , then switched to the AUX tank when the OEM ran low (another 3.5 gallons). and then we knew we had to find fuel in the next 150 miles....

I was riding my Goldwing so my range was about 225 miles and this worked well for US.

You may have to refigure the storage and hauling to move toward saddlebags rather than a trunk - but it solves your problems for about $250 (http://www.tourtank.com/ )

[tom203]

Sure, but is this setup legal ? and how would your (or their's) insurance company feel if you had an accident?

[Wingsconsin]

Confused I am...

Sure, but is this setup legal ? and how would your (or their's) insurance company feel if you had an accident?

Legal -- Yes.
Insurance company -- No problem - Why would they care..?
Baffled and legal Aux tank. Vented properly. Why would it be any different than putting on a LARGER TANK . Because of the location...?
Take a good look at some bike gatherings for other modifications to bike oem designs and you will see many things not original.

Only once did anyone confuse the tank with something else...at Memphis bike night...

[Wingsconsin]

We even added LED lights

We added running lights to the structure to be more visible too...

[Doughboy]

It looks like you have a trunk mounted on the rear -- maybe on a rack of some sorts..? If so ...then you can mount an Auxiliary Fuel tank back there and run the fuel line towards the carbs. By adding just a small tank you can add another 3.5 gallons of onboard fuel, be below the rack weight limit, and extend your range by nearly double..

Here is a picture of what we did to my Sons CX500 Custom in 2012. His tank held 2.2 gallons and even at 55 MPG the range was only just over 110 miles... We went to Tennessee that year and he wanted a longer range..an additions 3.5 gallons added another 160+ miles to his range...

You can see the tank on the rack in this photo.
running the fuel line is easy -- put a manual petcock near the tank (by the riders hip for easy switching) and a "T" fitting in line on the fuel line below the petcock on the tank but before the carbs. Gravity feeds the fuel into the carbs just like ti was coming out of the regular tank.

What we did was use the OEM tank as the MAIN (2.2 gallons) , then switched to the AUX tank when the OEM ran low (another 3.5 gallons). and then we knew we had to find fuel in the next 150 miles....

I was riding my Goldwing so my range was about 225 miles and this worked well for US.

You may have to refigure the storage and hauling to move toward saddlebags rather than a trunk - but it solves your problems for about $250 (http://www.tourtank.com/ )

Nice idea, and it may do well for longer trips, but will not work for me at this time. As I said, the wife rides with me and if I take away her storage for purse, extra coat, hair stuff, etc I will be riding alone. We tried saddle bags but the bike is not that big so it takes some of her foot area away and she did not like them when I had them.