GS850G Rusty Gas Tank question

[sf-nathan]

I just got a cheap GS850 'project bike'. Its my first four cylinder. I've had a few GS450's.

I saw a tip about using a chain to knock out rust from the inside of the tank. Do I need to worry about damaging the fuel sending unit? Any other tips about this?

thanks,
nathan

[SqDancerLynn1]

Take the sending unit out, you should coat the tank also with Kreem
or some other methoud

[sf-nathan]

"Take the sending unit out" - Cool, is there a gasket that I should order? I don't have the book yet.


thanks,

[SqDancerLynn1]

It's a rubber seal so you should be able to reuse it

[DaveDanger]

An alternate method to help break loose the rust is to drop a good sized double handful of hardware (make sure its all steel, and no stainless) inside and to close up all the openings. Do remove the petcock and the fuel quantity sending unit. When I did mine I fabricated a couple of small pieces of sheet metal and simple gaskets to close the openings. The filler neck I closed with a 1 1/2" plumbing plug that is basically a rubber stopper with a bolt through it with a wingnut on the top. Lube it with a tiny bit of silicone spray and push it in and tighten it good. Fit perfectly. A little bit of water inside will help as well to wash loose the flakes. Shake that tank like there's no tomorrow and keep doing it. When you're all done, drain the water out and shake out all the hardware and pull out what doesn't shake out with a magnet. Rinse a few times and dry it as thoroughly as possible. You can not get the inside of a fuel tank too dry. I dried mine as well as I could with a shop vac, then propped it on it's side and placed a pair of 500 watt shop lights right up against the bottom tunnel of the tank for a few hours. The heat dries every drop out. IF that does a satisfactory job of removing the rust, reassemble the components and reinstall the tank to the bike and fuel it up to prevent more rust forming. If it's still not as good as you'd like, check out the variety of tank sealers that are available. I've heard Kreem? is good, and I just completed my own tank with Por-15?. Worked phenomenally well.

I can't emphasize enough to make sure and get all the water out of that tank. A customer of mine (retired Harley Dealer) stopped and mentioned to me while I was rinsing mine out that at the very least, I needed to park the tank upside down while it air dried. You absolutely do NOT want water to begin rusting again down in the tank base seams. That is the worst place for leaks to start. The high wattage shop lights make it a moot point.

[JayH]

Yea what Dave said. I looked at the post and just wanted to say that putting acid in the tank will do a much better job than water.

POR15 does sell a kit that has everything you need to prep and coat the tank. I had access to lots of 2.5" drywall screws and used ~3lbs on them to scrape all of the rust out of the tank. Feel free to ask more questions if needed.