Fuel Tanks Rust Level

[lad]

What level of rust in a fuel tank do you consider 'concerning'? Is it zero tolerance.

i just got a 00 cali, wanted to check the internal strainers, they weren't as bad as I thought...









Still some crud there, I took them apart and cleaned them and shook the tank, I could hear a few rattles so I turned it upside down and a few chunks came out :









Not sure is it metal or residue or both. I can see that pipe for the overflow from the pressure regulator is quite rusty so it could be some of that either.

Then the underside of the tank is a bit brown but quite smooth...





How would you approach this?

I have used tank sealant before but it's long and toxic and that was for an actual pinhole-leak.

Then there's things like kurust/rust-convertor for the underside, the paint is already ruined, or just steel wool and lacquer? Or nothing at all?

[moto-uno]

That looks pretty awful to me . I wouldn't dream of trying to coat it until the rust has been removed .  Peter

[Perazzimx14]

I wouldn't dream of coating/lining the tank interior unless it was actually leaking. Tank liner is a last ditch effort.

[Scout63]

I don’t seal tanks anymore.  It’s an awful job and if it doesn’t work you have a mess.  I really like MetalRescue.  It’s non toxic and you can get it in five gallon buckets.  Pour it in and let it sit for a day or so.  It will dissolve rust down to clean metal.  Strain it out through a coffee filter back to the bucket and reuse it a few times.  It won’t hurt paint unless there is rust underneath it.

[Sasquatch Jim]

 Bummer!

[Groover]

I'd do an Evaporust treatment, easy, safe and cheap, then flush then keep the tank mostly full year round.

[n3303j]

No reason not to line the tank with Caswell "Dragons Blood". Bonds any remaining debris so it will never contaminate filters. Ensures that the tank will never rust no matter how much water on board. Cheap insurance that any "almost pinholes" never progress to leak status.

It's preventative medicine. Coat it and never again worry about tank problems.

[Canuck750]

Fill the tank with Evaporust and let it sit for a week or two, shake it up every now and then. If you have an aquarium heater tube insert it through the filler cap, heat spreads up the process. If you want a quicker fix dilute muriatic acid 50% with distilled water, wear rubber gloves and work outdoors with eye protection, fill the tank and in a day or two the rust will be dissolved.
With either option rinse with warm water and dry then rinse with methyl hydrate to get all the moisture out.

[lad]

I'd do an Evaporust treatment, easy, safe and cheap, then flush then keep the tank mostly full year round.

Why only mostly? Not sure can I get evaporust over here but I'll check it out, or something similar. Thanks

[lad]

No reason not to line the tank with Caswell "Dragons Blood". Bonds any remaining debris so it will never contaminate filters. Ensures that the tank will never rust no matter how much water on board. Cheap insurance that any "almost pinholes" never progress to leak status.

It's preventative medicine. Coat it and never again worry about tank problems.

What do you do with the petcock and strainer for this procedure? Just plug the opening with something?

[n3303j]

What do you do with the petcock and strainer for this procedure? Just plug the opening with something?

Plug or mask as required. The product does not remove easily once it has set.

[Groover]

By mostly I meant don't worry about it not being full if you just park it for a month empty. Keep it full for longer term storage like during the winter.

[pete mcgee]

There is another option.
Electrolysis
Plenty of youtube vids on it
Requires vinegar,  a low voltage power supply. A steel electrode, some wire to connect it all up.
I used this method to remove the majority of rust from a R100rs tank that had been sitting half full of very old fuel for 23 years.
Its been in storage for 4 years since then, I need to finish passivaating it and seal it.
It works well, non toxic,cheap.(apart from using science is the cost factor enough for Guzzi content?)
Well worth looking into.

[lad]

There is another option.
Electrolysis
Plenty of youtube vids on it
Requires vinegar,  a low voltage power supply. A steel electrode, some wire to connect it all up.
I used this method to remove the majority of rust from a R100rs tank that had been sitting half full of very old fuel for 23 years.
Its been in storage for 4 years since then, I need to finish passivaating it and seal it.
It works well, non toxic,cheap.(apart from using science is the cost factor enough for Guzzi content?)
Well worth looking into.

I thought you might damage the outside of the tank? Will look into it though, good shout.

Might just fill it with coca cola and a few screws tied to some fishing wire and shake it for a week or two, quick alkaline wash, acetone rinse and fill her up...? It doesn't seem like bad rust compared to some of the tanks i've worked on, like when I look into it, it looks pretty perfect, so I'd say there's just a few spots, or that return pipe..

might be eating my words in a few years either

[ampm7]

I don't know but that looks bad and should be dealt with as soon as possible. I use KBS coatings and just did on my '98 EV as it had been neglected for some time and I have done several tanks before. The problem that I had on the EV was that the liner was coming up. On my Harley, the liner was shot so I had to use stripper to remove the liner. This is a very tricky job. The tank was done like a late 30's Knucklehead and I didn't want anything to affect the paint job. Needless to say, a lot of prep and protection. Their system is 3-fold in that they use an environmentally friendly cleaner, then after drying you use a rust inhibitor, and then after drying you put in the paint but carefully plugging any holes before any paint. I used a combination of grease (inside the fuel feeds to keep paint from adhering) then cut down wine bottle corks fastened with electrical tape. Toss and turn the tank thoroughly to seat all the paint and do it often over a 1-2 hr interval. Luckily, on the EV I was able to use a knife and cut away any loose liner as that was the area that was affected where the fuel nozzle sprays fuel. Take your time, this is not something that is done in a day. I did the EV over a 10 day period to insure that everything was dry and cured.

[lad]

I don't know but that looks bad and should be dealt with as soon as possible. I use KBS coatings and just did on my '98 EV as it had been neglected for some time and I have done several tanks before. The problem that I had on the EV was that the liner was coming up. On my Harley, the liner was shot so I had to use stripper to remove the liner. This is a very tricky job. The tank was done like a late 30's Knucklehead and I didn't want anything to affect the paint job. Needless to say, a lot of prep and protection. Their system is 3-fold in that they use an environmentally friendly cleaner, then after drying you use a rust inhibitor, and then after drying you put in the paint but carefully plugging any holes before any paint. I used a combination of grease (inside the fuel feeds to keep paint from adhering) then cut down wine bottle corks fastened with electrical tape. Toss and turn the tank thoroughly to seat all the paint and do it often over a 1-2 hr interval. Luckily, on the EV I was able to use a knife and cut away any loose liner as that was the area that was affected where the fuel nozzle sprays fuel. Take your time, this is not something that is done in a day. I did the EV over a 10 day period to insure that everything was dry and cured.

It could be the liner alright, is there really a need to remove it? Wouldn't a tank sealer just bond with it and seal it all up anew?

[Navydad]

Toss in a hand full of smaller screws, bolts, nuts, etc. Wrap the tank in a heavy padded blanket like furniture movers use and tape it thoroughly. Put it in the clothes dryer for an hour or so and let it tumble. Here's the most important part. Make sure the wife is away for the afternoon. DO NOT GET CAUGHT. 

[ampm7]

The problem I had on the Harley is that the liner was coming up in large pieces and was affecting the flow of fuel through the petcock filter. So, it had to be done. If the liner is questionable, it is possible to use a lot of paint to cover the semi-failed liner which is what I did on the EV. Whatever paint you use prep is very important and drying thoroughly. I left the tank out in the sun but you can also use a heat gun through the filler hole on the lowest setting leaving on for 5 minutes then turning off.  Wait till the tank cools down and then do it again and repeat as necessary. I also blow compressed air into the tank. These are 5 gal tanks so, enough paint to do 8-12 gals will cover everything but you have to rotate the tank all the time over a 2+ hr so that the paint covers everything. I did my Ambassador tank about 7 years ago and it is perfect. It is really important to follow directions and don't be in a hurry. Once done you will never have the problem again.       

[malik]

Just about to test drive the KBS kit on the V7 Special tank. When I cleaned out the sand, gravel & debris from the tank after the fuel filter exploded, I found RUST on the inside lining, down from the fuel cap (I'm a zero tolerance type when it comes to rust in tanks). The first difficult bit has been fashioning a plate to cover the fuel pump hole. I made up a gasket from silicone sheeting OK, then cut out a piece of old 3 ply. That didn't work - the drill bit fractured the bottom veneer. Now I've cut up a cheap plastic breadboard. It has been a problem getting the 6 screw holes aligned - the last thing I want to do is strip any of those fine threads. I used the rubber gasket as a template, but didn't allow properly for its flexibility. When that problem is solved, I'll hunt up a sacrificial cap for the top hole, then start the manhandling of that awkward lump - not looking forward to that bit. Could be somewhat tiring.

[pete mcgee]

Malik,
Ive had very good results using aluminium tape to cover holes in tanks when I ve sealed them, 1, 2 or 3 layers depending on location and requirements.
Worth considering
Cheers

[malik]

Thanks, Pete. I'll look into that. Can't hurt to have some on hand, leaks are likely. It's a messy business.

[JJ]

A few years ago, I bought a 1978 Honda GL1000 ("Naked Gold Wing") that had some rust in the tank. 

I had the carbs rebuilt and a local GL1000 specialst mechanic talked me into "nickel coating" the inside of the gas tank...It was the best $250 I ever spent!!

I remember more than a few of my cheap "GUZZI GEEZERS" friends suggested I just run white vinegar through it..."Blah-Blah-Blah!"....and it would be just fine...

No..this was the right long term decision and with the being carbs rebuilt, it ran like a top for the entire time I owned it.  That Naked Gold Wing was a fun bike to own and ride - "The Root Beer Float!"

Just sayin'....




gamma iota sigma

[lad]

I presume that fuel return pipe would need to come out before I seal it, is there much to that? Weird size washer/o-ring?

[lad]

There is another option.
Electrolysis

This is the way. going to do it tomorrow. i'm not even going to seal it after, once the rust is gone i'll just fill it and that should be a preventative.  I heard sodium carbonate u
is the proper solution, not vinegar, hard to find in Ireland but i can make some from baking soda

Science!

[Gusable]

I just got done with the KBS coating second step of the etching product. Drying now. Very pleased.

[Guzzistaracing]

Used tank sealer for my NF tank. I counted 33 pinholes before I stopped counting. Soldered the biggest and used tank sealer. Thought it was easy and good. Never had a leak after that.

[krglorioso]

Owning a Breva 750 means never finding rust in your tank. 

Yes, it is a minor nuisance to run non-ethanol fuel, but there is a station very near my home and the 90 octane good stuff is cheaper than the 91 octane gasahol.  Fuel consumption steady at 57mpg. 

Guzzi did the right thing with the Nylon tanks.  Not their fault the US politicians decided to queer good gas with ethanol added. 

Ralph