Dirty Gas Tank

[Samelak]

I switched over to a paper element fuel filter since having my carbs rebuilt by Mike and I have noticed the filter catching a tremendous amount of dirt. Its to the point that I only get about 250 miles before the filter is clogged. It does not look like rust and looking in the tank I I don't see any scale. Its mostly shiny looking inside. When I shake the filter out, it looks like a silty mud. Its very fine and appears to be grayish-brown. Any thoughts on what it could be and how to get rid of it?

[Jeff Bennetts]

If you don't think its rust just buy some Marine Clean, it's made by POR-15 and is part of a three step process to seal a tank sold in a kit by them, you can buy it separate and a lot of car parts store sell it, the next step is the etching solution they sell, if you do have light rust but don't need a sealer use it too.

[steve murdoch icoa #5322]

30 years of crappy gas will leave a lot of deposits in a tank.
I had a similar silt in the float bowls that i thought was dirt but it had a slight reddish hue and was indeed fine particles of rust.
Not being able to see any corrosion, i went with a milder cleansing solution and tried the molasses wash.
A week of sloshing, an inline gas filter and i was good to go.

[kbart1]

i agree with jeff, i used the por15 heavy duty tank sealing kit and it works SWEET! for what it's worth the marine clean and metal prep is the best stuff i've ever used but wear gloves!

kent

[Kool_Biker]

After trying and failing on numerous occasions to shift various powder like, non rust deposits in my 79 tank, what worked surprisingly well was acetone.
It was very satisfying to see lots of curd at the bottom of the reclaimed acetone container after allowing it to work all night in my tank.
Aris

[Jeff Bennetts]

There are many cleaners from acetone to molasses that will work fine but if you have rust in your tank you need to follow up with something that will stop the rust from reforming like the Metal Prep or some other kind of etcher.

[mac.]

Whilst trying to find a company to clean my tank out, I've come across a company that galvanises the fuel tank. I was told that it is done regularly on bike tanks and that they just need to drill a hole in the tank to allow the galvanising to drain out. Not too keen on this idea. Any thoughts on the galvanising and the drilling?

[barryadam]

Whilst trying to find a company to clean my tank out, I've come across a company that galvanises the fuel tank. I was told that it is done regularly on bike tanks and that they just need to drill a hole in the tank to allow the galvanising to drain out. Not too keen on this idea. Any thoughts on the galvanising and the drilling?

Any of the "cleaners" (including molasses) will use acid and end up etching the surface of the steel. Think of it as removing some of the elements of the surface layer material.
Now it's clean, but immediately susceptible to further rusting.

To protect the clean steel surface, I went with a coating of nickel. If you are using acetone, or any other paint removing cleaners, you are probably doing a re-paint anyways. No more worries about flaking coatings, or lack of adhesion, especially from the filler neck or petcock threads.

Galvanizing is plating with zinc, which is a good idea, but if you can find nickel, it's more durable. If you have to galvanize, hot dip is better interior tank coverage than electroplating, which is line-of-sight. Not sure why they have to drill a hole. The tank already has holes - they just need to rinse well.

Barry

[mac.]

Thanks for the information. I'll find out some more and have a decision to make soon. I assume that this is only galvanising the interior?

[NobleHops]

Here's another vote for a good cleanout with Marine Clean or its equivalent. I did the entire process on my red bike recently including the liner, and it came out great. Marine Clean without the following phosphoric acid etch should not cause any problems if the tank isn't rusty. If you use the metal prep stuff then definitely follow through with the coating.

[FalldownPhil]

Here is one more alternative !!
They are not cheap, but they are the best. My last trip in here with two CBX tanks to be done, I just missed Jay Leno
dropping off a tank from one of his Brough Superior's.
https://www.google.com/url?sa=t&rct=j&q ... cmKLFYZYAw
Best,
Phil