GS550L / E Fuel tank swap

[Guest]

Hey all. Hopefully this isn't a repeat post but couldn't find through search. Looking to remove the tank from my 1979 GS550L and replace with a 1978 GS550E model tank for a brat build. Looking at pics there is a noticeable size difference between the two but was curious if anyone knows if it is a direct fit? Looking at some parts catalogs online it appears the frames are the same but was hoping to get a definite answer before purchasing the tank from ebay. Thanks!

[Steve]

They likely have different mounting points at the front, the E tank mounts farther forward.

Once you get the tank mounted there, be ready to get two good-size dents in the front, because the L forks are farther back than the E forks, they will hit the tank.

And it's not simply a matter of replacing the forks, because the triple trees are also different, which is what pulls the forks back for that "chopper" look.

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[Oregonian]

Bummer! Didn't realize the triples were different too. Looks like I will need to upgrade forks but stay in the GS family because I already have a spoked front wheel I want to use. Thanks for the help!

[Steve]

The L models were trying to cash in on the "chopper" look, so they flattened out the angle on the triples to pull the forks back, put the axle in front of the forks and extended the forks a bit below the axle to make them look a lot longer. In order to pull the forks back, they had to have a smaller tank, so why not go teardrop-shaped, put the higher handlbars and a stepped seat on it. Oh, let's do chrome fenders and headlight bucket while we are at it, you now have an L.

It's all part of a system, it's hard to change just one part unless you know how it all interacts.

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[Oregonian]

Great info, thank you!

[AMK]

Keep the L as is, they are nice.

[sam000lee]

I have an extra GS450L in pieces that is kind of a long term "don't care about cutting up" project (i.e. the one I don't care about not having running so can mess around with a lot). Going for a more horizontal look than what the L had. I cut off the front mounting posts and welded them in lower as well as lifted the back up by about 1 1/2". There's a seat from a T model on there, too, which makes it a little flatter. Not sure if this is helpful since it's with the original tank but I think it looks a little cooler than it did...

[Steve]

You are going to run out of gas before the tank is empty, but I guess you're ok with that.

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[sam000lee]

You are going to run out of gas before the tank is empty, but I guess you're ok with that.

Right - hadn't thought about that haha. This bike is a long way from anything right now so I'll worry about it later.

[Oregonian]

So I have a line on getting E model forks, triples, and tank for a great price. From the sounds of it, mounts will have to move to get the tank to sit in the correct position but am confident in my welding and fabrication abilities to make this happen. I guess all I really need to know now is if there is any other differences in the two frames aside from tank mounts? If the frame geometry is entirely different, not sure this is something I want to tackle. I would have to think the frames themselves would be the same but am having a hard time finding any information online.

[Steve]

Steering geometry is the same, but there are probably differences in the seat and tail section area.

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