rusty gas tank

I was reading Ron's directions for taking care of a rusty tank. I just have a couple of questions. First of all, i have a shut off valve I'm going to be replacing, can I just use that instead of rigging up another way to drain the acid?

Also, just so I'm completely clear, once I get the acid out, then I need to rinse with water and then just hope it dries out before more rust can form? My tank is not detachable. How long should I wait before adding the dry gas?

Thanks - it's going to be my project this weekend and I just want to get ready.

Re: rusty gas tank

Hi,Cookster! I haven't seen Ron post for a while,but didn't he recommend blowing it out(drying it with compressed air) and then using the drygas? I may be getting mixed up with another post.Be careful and wear goggles too,cookster,`cause that acid ain't no fun.Keep a hose handy.BYE!

Re: rusty gas tank

Okay, the whole thing is making me nervous. I'm just not careful enough to deal with the acid, I don't think. I have found some local folks who could sandblast the tank. Any downside to that?

Re: rusty gas tank

Right,Cookster! The acid treatment is a lot easier when you have a removable tank.If it were mine.,I wouldn't sand-blast it,I'd do the acid thing.But see,I'm a Chemical Operator and have been flushing and cleaning for years.That's why I recommend a water hose be handy that's within reach with your eyes closed.We use pressurized portable eyewashes out in the field work.Here's what I'd do if it were my bike:Drain the gas,fill the tank with used or new motor oil, drain this out,drain yourengine gearbox, remove any battery or other liquids,and HANG the bike upside-down so the gas cap opening is bottommost.Take a 3/8" cable about14" long or so and fray one end ,also bending it 45-90'. Chuck the other end into a 1/2" drill and that cable will knock the worst rust out of the tank without hurting or denting it.Then take an air hose(you've got goggles on now)and blow the heck out of the inside of that tank.Check the inside for particles that don't blow out and get them out also;then blow it out again.Restore the bike upright,remove the old no-good petcock,and flush thru the tank with a generous amount of gas, and install your new petcock and filter.Fill her with all the fluids you removed and start her up.Check your fuel flow by removing the hose at the carb every so often and you'll know if you need to remove the petcock valve and clean the filter.Use gas without ethanol and methanol and you'll keep rusty tanks to a minimum.(MARATHON or SHELL is good) BYE!

Re: rusty gas tank

XBrandon EdgeX /

I sandblasted the inside of my tank. It worked pretty good from what I could see, and my fuel filter has been clean ever since. The only downside is getting the sand out. I had to run compressed air through it for about an hour! Then, I rinsed it out with gas a few times. I tried acid, but the stuff I got was too weak. I used "Lime Away" and it didn't do anything. I couldn't find any Phosphoric acid and I heard that muriatic acid requires a coating after using because it's so corrosive and will start rusting right away if you don't paint it or keep the tank full of gas all the time.

If you sandblast the tank, you should use a fuel filter (well, you should use a fuel filter no matter what).

Re: rusty gas tank

Chris Robertson /

Hi Cookster:

If you use phosphoric acid (i.e. automotive rust remover) you don't need to worry about rust forming right away. The phosphoric acid reacts with the metal and makes a protective "tarnish". You can rinse the tank out with water (followed by gas) without fear.

I no longer recommend using muriatic acid because it doesn't have this tarnishing quality --rust will begin to form immediately.


Re: rusty gas tank

Ron Brown /


I have not looked at my instructions lately, but the dry gas is used to remove the water. Use it right after you rinse the tank with fresh water. You can use the old pet cock as a plug as long as it does not leak.

Follow the instructions regarding water hose available and on and wearing old clothes and you should be ok.

If you want to test the acid before you use it, put some in a plastic bucket with something rusty and see how long it takes to work.


Re: rusty gas tank

this is a major problem with no guarentee this it'll work.

i spent months dealing with this problem. there is one sure fire way to solve this forever tho. and it's what I ultimately did.

get a plastic gas tank, (snowblower, chainsaw, whatever. look around, there are plenty of them out there, average cost 10$) and mount it on the rear rack or under the seat. solved my problems and now i get to ride without the worry of my peugeot stalling.

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