Tank water drain derusting

[mandar]

I searched around but I didn't find anyone else having this problem. Turns out the reason I have needed to derust my tank twice in the past year (electrolysis saved my day) is that the water drain pipe in the petrol tank has rusted so thoroughly, that it is completely blocked. So any time it rains, and my bike is not covered, the water just spills into the tank and soon enough, begins rusting the tank.

I hadn't found POR here in France (or any decent alternative suggestions from the local mechanics here), so I've stuck with electrolysis for derusting my tank. But I don't think electrolysis will work on unclogging the drain pipe. In case I use muriatic acid or something, I would need POR-ish stuff, right?

The problem is not urgent in the sense that even if there is a hint of clouds, I use a giant tank cover while riding to keep any water from even touching my tank. However, that just means I can't carry too many things in my topbox. :-/

Does anyone have any suggestions?

[mysterious_rider]

Can you not get a seethrough map tank cover. So at least it's going to stop the water getting in?

[bombsquad83]

Can you take your fuel filler cover off, and then run a long pipe cleaner down the drain hole to clear the blockage?  I would be careful with acid, because if the tube is badly rusted you will eat a hole right into your tank.  Same goes for the pipe cleaner method I suppose...

I wonder if you have a hole in the drain tube that allows water to drain into the tank.  You could check by putting just a little gas in the drain hole with the tank almost empty.  If it drains, but doesn't come out the drain hole in the bottom, then you have a hole in the tube that goes into the tank.  If it doesn't drain at all, then it's blocked.

[mandar]

Yea, map tank cover is what I'm gonna buy. But that's a temporary solution and I might have to sell the bike by the end of this year. Should fix this before that I guess.

I do know that there is no hole. I spent a couple of days adding wd-40 each day, letting it sit and scraping out some rust. And after the electrolysis this Sunday, while putting the gas back in, some of it ended on the top and in the drain hole. It stayed there till it just evaporated.

[bombsquad83]

This makes me feel a little better about all my tank woes.

[adidasguy]

WD40 won't dissolve rust. Use a rust dissolver. Take tank off. Then go at it from both sides with a long thin drill. Twist gently by hand and you'll get it cleaned out.

Then check the drain hose. Only way the pipe in the tank would rust is if it had standing water. The rubber hose must be pinched .

[bombsquad83]

I would be careful with the drill bit.  Just FYI that tube is not completely straight.  At least I know it's not in my '93 model tank.

[noiseguy]

Use vinegar straight from the bottle. Takes a day or so to derust, but is far less toxic than muriatic acid. And easier to dispose of.

[adidasguy]

You could use a stuff wire with a roughened up end. The point is you need to twist and work something down through it along with rust dissolver (something better than WD40).  And go from both ends of the tube. Probably the wire of a stiff pipe cleaner would do. maybe a coat hanger wire with the end flattened like a chissel to grind out the rust as you twist it.

The emissions air vent on a Calif. tank has a sharp bend. I recall the fuel cap drain is pretty straight. A long thin drill would be somewhat flexible. Don't use a drill - wist gently by hand to work the rust out. Free a little rust, then clean out the hole. Repeat.

As some rust gets free, it will clog up things and you need to get it out. Like drilling a deep hole in wood: you drill a little then pull the drill out to get the chips out then go back in. Kind of like sex.
Rust is softer than the un-rusted steel so should be able to get it out with a little patience and work.

[mandar]

This makes me feel a little better about all my tank woes.

It's been painful here. The first time I discovered rust last May, the mechanic here told me to just "let it be" (in French of course) since the "rust will just come back".

WD40 won't dissolve rust. Use a rust dissolver.

Until yesterday I thought WD40 was the solution to all rust problems. :-/ Did a little wiki and other research.

Then check the drain hose. Only way the pipe in the tank would rust is if it had standing water. The rubber hose must be pinched .

Yea that was one of the problems. All my problems (rust, carbs, battery) in the past year began because I left my bike standing for 1 month without a cover (yea, I know). Also, I should have checked better before buying the bike. Can't count the number of times this forum has saved me. Thanks!

[twinrat]

Your water drain hole is not for draining water( THATS JUST A PLUS) its  there  for if you over flow your tank while filling with fuel and the hose directs it away from your red hot motor.
Take the tank off ,pull the hose off and clear from below.

[noiseguy]

WD40 will prevent rust from forming if the tool is kept relatively dry and covered... will also displace water if it's wet (WD is for Water Displacement.) It won't remove rust or prevent it on metal left outside.

The overspray is also really great for keeping paint from sticking to things (expensive lesson.)

[adidasguy]

Once you get it out, use something like Eastwoods Rust Encapsulator or Rust Converter. Pour some down the tube then with a long cotton swap kind of thing (make something) run it up and down to coat the inside of that tube. Problem should never come back. You could also use a fuel-proof paint, but the rust converter penetrates the rust and seals it rather than just covering it over.