Rust In The Tank

[stp1stp]

I am working on a 1980 GS750L. Finally started on the tank. There is rust inside it. What can I do about this? The last bike I had had some kind of coating on the inside but it's probably expensive. What's a inexpensive what to fix this.
Thanks

[speedway17]

I have an '83 GS 750 it had a similar problem with the tank only there was about an inch of rust in the bottom of the tank when I got the bike. I took the petcock and fuel gauge out and sealed the openings. I then put some small nuts, bolts, BBs and a couple quarts of gasoline in the tank. I then shook the tank...........alot, it gets tiring after a while so I would just come back to it every once in a while and shake it some more. I emptied the tank and rinsed the inside w/gas and repeated with the nuts, bolts and gasoline shaking business a few times. I never did get rid of all of the rust coloring in the tank but I think I got all of the loose debris out. I installed a good inline filter between the petcock and the carbs, have never noticed any collection of particles in the filter. In my opion this method worked OK

[J_C]

If its leaking then you can use the por15 sealer. It has a cleaner and sealer. If it's just rust, then there are several products etc out there.

I picked up some phosphoric acid from Lowes. Apparently this will strip the rust and leave some kind of substance behind which hinders flash rust. I have not yet tried it, but I am considering doing it tomorrow. Will let you know how it goes if so

[stp1stp]

It's not leaking just rust. I would like to know how that acid turns out. The nuts a bolts is a good ideal. Thanks for the tip.

[sandman900ss]

First: the old nuts and bolts rattle tip is a hassle and wastes time getting them all out- a much better, easier solution is to thread in a length of fresh/new hardware store plated chain (not bike chain, the type for hanging things or tow hooks instead). Rattle that around with fresh gasoline and repeat until the gas that dumps out is clear. All you have to do is grab one link of the chain with a claw tool from Sears to remove chain from gas cap hole when done.

Second: "Kreem" used to be the old recommended two part tank liner kit sold in motorcycle shops. It's MEK (methyl ethyl ketone) based, and so many people do the preparation poorly, it often fails and peels up in sheets, clogging the fuel system worse than the rust did. I've had good luck with it in the past, but I followed the instructions. If you have to deal with a poorly Kreem lined tank like I have, MEK from the hardware store dissolves Kreem like magic. It's truly nasty stuff though, so do it OUTSIDE for sure, wear gloves, and be very careful to protect you tank's paint job of you're not repainting.

Third: there's now a much better, accepted product for lining gas tanks as mentioned above: POR 15. It's been around in the vintage automotive restoration field for years, and they now sell small kits for motorcycles. It gets the name from the fact it's got soem porcelein in it, and it flat out works great-IF you do a great prep job and follow the instructions. It's the only way to go now if you want to do the job right the first time. I notice it's always available on eBay if you search, or direct.
http://www.por15.com

There you have it. Good luck!

[blackwolf]

Us navy jelly it take out the rust,then clean with gas about half gallon do this twice.This should work it did withe me ,you can find navy jelly at the auto parts stores.

[chuckycheese]

Por 15

I've read about the POR15 stuff and I imagine it's quite good. As an alternative, you could always have a shop do it for you. Four years ago, I took my tank (same as yours) to a shop that works on old bikes and paid them $80 to line it. The stuff they did it with looks like red, translucent finger nail polish. After 4 years, it looks exactly like it did when I got it done and I've never had a problem of any kind.

I'm sure I could have done it cheaper but I don't think I could have done it better (..and probably not as good.8-[ )

[J_C]

Tried the phosphoric acid today. The areas I was able to reach with a small bottle brush were fantastic. The areas I couldn't reach.... now I have liquid rust that comes off completely if you run your finger across it but wont rinse off with water.

I'm going to try again this week with a stronger concentation and more agitation. Will let you know how it goes.

[Billy Ricks]

http://www.sudco.com/rustol.html

[RacingJake]

Once you get rust inside your tank it's there to stay. You can clean it out but it will only return. Never tried sealing the tank but that would be the best thing as long as you can do it right. When I cut the guts out of my gas tank you wouldn't believe the amount of rust and flakes that came out of it after I'd clean too.

[Billy Ricks]

Once you get rust inside your tank it's there to stay. You can clean it out but it will only return. Never tried sealing the tank but that would be the best thing as long as you can do it right. When I cut the guts out of my gas tank you wouldn't believe the amount of rust and flakes that came out of it after I'd clean too.

Read the story on Rustol.

[J_C]

There's got to be some way to cure it, even if it takes going to a radiator shop to have it done, right? If the acid is able to etch out the corrosion, then there shouldn't be anything to promote it coming back I woulds think.

But I'm no chemist