Cleaning rust out of the gas tank

[matteapolis]

Ok, I've got a 1980 gsx750 and the tank is pretty rusty on the inside. It sat for about 10 years with gas in the tank and has a really strong varnish smell to it.
My buddy who's got a shop said to use muriatic acid and I bought the 2 gallon kit that Home Depot sells.
I've read a little about what to do online, but would appreciate some help with my tank.
I took some photos here:


1.My questions are, does anyone have easy detailed step by step instructions on how to get the rust out with muriatic acid?

2.Is it ok to leave the petcock & float in the tank when I put the acid in the tank? If not what should I plug the holes with to keep the acid from running right out?

3.Do I need to completely fill the tank with acid/water mix?

4.About how much should I expect to pay to replace the petcock? the filter on mine is toast. Same with the float. It's pretty rusty.

5.Am I better off going to the salvage yard and getting another tank altogether?

I'm in Portland, OR and there's only 1 salvage yard in town. The guy can smell how green I am as soon as I walk through the door, so he's ebaying prices on used parts for me.
I paid $55 for an old seat and $70 for a rack of carbs. He's saying my bike was only made for one year, and parts are hard to find and I'm lucky he's got em, etc, etc.
I got the bike for free, so I don't mind putting money into it, I just don't want to pay twice what I should be on every little thing I have to replace.

Anyway, I'm rambling. Any help is surely appreciated. I want to knock everything out in the next couple of weeks and get this bike on the road. I wanna feel like Mad Max a couple of times this summer before the rain comes back...

Matt

[Nessism]

I strongly suggest some other derusting chemical. HCl is too strong for the tank and will also eat metal off the tank in addition to the rust. Phosphoric acid is better since it won't attack the good metal. Some people use vinegar with good results too. Oxalic acid is also good and won't eat the good metal. Evaporust is best of all, but a little more money.

[Dave8338]

CLR.




The stuff works.





Don't make me provide, you with a link...

[chef1366]

I used Evaporust and a bunch of bolts.
Then line the tank with POR-15.

[BassCliff]

Hi,

Look on my little website for a couple of tank cleaning guides.


Thank you for your indulgence,

BassCliff

[hjfisk]

I just leave the sending unit in and petcock , fill with white vinegar let it soak a couple days tipping the tank and rolling it around so everything can soak, drain after about 3 days and remove the sending unit ,petcock , and cap, rinse with high pressure water,then spray down with WD40 or some other oil to prevent flash rust. It is a little slower than some other methods but also not as aggressive. Some of the other methods can be alittle more aggressive and may make holes if left to long. vinegar works very well and is very cheap at walmart

[tkent02]

Electrolysis is another option, it's cheap and works well but it's time consuming. Done about ten tanks now, they come out very nice. You tank doesn't look all that bad, unless there's a lot more rust in the bottom. Easy to fix with electrolysis.

[Rkt-Rch]

Again POR15 Rocks.. Did my tank about 2yrs ago and not a leak to be found and my tank had LOTS of pin holes and some pretty large ones also.

[dieseln]

I've used the Vinegar - works great... that m-acid is very nasty stuff

[matteapolis]

Ok,
I returned the Muriatic Acid after the advice given here (thanks!).

I picked up 2 gallons of CLR instead. I have a bag of roofing nails to throw in the tank as well.
Do I just add the CLR and nails and shake and roll the tank once an hour?

Is it safe to leave the gas cap, sending unit & petcock in the tank with CLR?

Also, where can I get a new rubber gasket for the sending unit?
I also need to replace the rubber gasket & the plastic filter on the petcock, mine are toast.

Again, all the help is really appreciated. Thanks!
Matt

[Nessism]

I prefer aquarium rocks over nails and the like because they are smaller and will get into all the nooks and crannies inside the tank. Never used CLR so can't help there in terms of whether it will damage the sending unit, but my advise is to make plugs to be safe.

Any dealer part source can get you those seals. Part Shark is one of the cheaper on-line sources.

[matteapolis]

Ok, I'm using the CLR on the tank now and it is coming out beautifully!
This is awesome! Gonna use CLR on a bunch of other rusted parts on the bike.

Another question. I read somewhere that after you de-rust your tank you need to treat it with something to keep it from rusting again.
Is this the case with CLR? Also, read that you can use WD-40 to treat the inside of the tank. Is this true? Cause it would be convenient, if so.

Thanks again.