Rust in the gas tank

Hello Everyone,

I have posted the details in another thread, but here I want to ask a specific question.

I am looking at buying a 1980 Interstate that has been restored. The person who did the restoration picked the bike up from someone who had let it sit for several years so this person took several years to go through everything. In the process of our conversation he did tell me that there was rust in the gas tank and he addressed this using a variery of methods from brushes and chemicals to electrolysis. We spent a great deal of time on the phone discussing everything that he did, and by what he said, I felt that he knew what he was talking about. He restores vintage motorcycle for a hobby, mostly triumphs, etc., and this was his first Goldwiing.

He states that he completed this project several months ago and has put about 1,500 miles on it and everything seems to be running as it should. I don't doubt that, but I have to wonder if the only way to truly deal with rust in the gas tank is to replace it and is it possible for rust to still exist and filter into the carbs?

The bike is located several hundred miles away so I want to be sure that I have addressed all my concerns before investing the trip to check it out. I would appreciate any input.

Good questions! My opinion? If he does motorcycle restorations and has cleaned the tank and run the bike for 1,500 miles, there is a good chance the bike has gas in it. If there was a rust problem, it would shutdown the carbs pretty quick. It is easy enough to get the tank out if needed, but you can also just take a peek inside the tank with a flashlight and check it your self. I know it doesn't help when trying to purchase and the bike is far away, but it does sound like that work has been done. The nice thing about GL1100 gas tanks is they are actually below the seat and not in the area above the engine like most motorcycles. It keeps the tanks out of weather extremes like sun beating on a cold tank creating moisture in the tank. The other thing is, these engines have fuel pumps and the tanks are not gravity fed. The suction on the pump will surely pull anything in the tank into the filter first. If the filter clogs (and it will if there is rust), the engine will slowly bog and then shutdown. Change the filter and have at it!

I have done a number of inspections and survey on equipment that is hundreds of miles away and I often can do the initial survey via Facetime on an iPhone or video chat on other phones. I would suggest you setup a video chat with the current owner and have the bike started up!

Thank you so much for the great and detailed information. As you can imagine. Buying a bike from a long distance is really nerve racking.

I was very specific about what he did about the rust in the tank. He did tell me that he addressed the issue by not taking the tank out and worked on it with it in the bike. He did overhaul the fuel pump and tested it separately by running fuel through it from an outside source. He also set up running the gasoline from the fuel tank in the same way several times until what was coming through it was clean and clear. And then of course he has put over a thousand miles in the bike after that.

From all that he told me it did seem like he knows about restoring bikes and from all the details, I was impressed about how methodical he was doing all this. He also didn't rush through all this but took several years to go through everything and I found that impressive as well.