Pinhole Leaks

[Kiwi_Roy]

Lately I have been noticing a smell of gasoline around my old loop. In the weekend a small blister appeared in the paintwork so I suspect rust has finally gotten through the metal.

I did treat the tank with Rust Mort but I think now I need to step it up a notch.

Any recommendation on a treatment that will seal against rust and the ravages of Ethanol.
Speaking of which earlier this year one of my white carb floats was found to be full of gas, I thought the white ones were supposed to be impervious.

Thanks in advance

Roy

[Chuck in Indiana]

Caswell epoxy, and the white ones are the ones that eventually leak. The good ones are NLA.

[Sasquatch Jim]

 A new tank will fix the leaks.  I had a Honda do that back in the eighties, that's how I fixed it.
 The fix was still holding gas when the bike was stolen nine years later.

[Antietam Classic Cycle]

Caswell epoxy, and the white ones are the ones that eventually leak. The good ones are NLA.

This ^^^.

[Kiwi_Roy]

A new tank will fix the leaks. 

Well I guess

Thanks Chuck, Charlie
Caswell ordered
I put in one of the original grey ones
Perhaps I could dip the leaky one in the Caswell as a spare, can't hurt to try eh!

[pehayes]

I did a Caswell on my Falcone tank about 10 years ago.  Spent two hours on the couch watching TV and gently rolling the tank in every possible direction to get the material to flow everywhere.  Remember to remove all fixtures and completely protect any threads against material intrusion.  To this day, the interior looks like it has been coated with crystal clear window glass.  Hard as a rock.

Patrick Hayes
Fremont CA

[Antietam Classic Cycle]

I did a Caswell on my Falcone tank about 10 years ago.  Spent two hours on the couch watching TV and gently rolling the tank in every possible direction to get the material to flow everywhere.  Remember to remove all fixtures and completely protect any threads against material intrusion.  To this day, the interior looks like it has been coated with crystal clear window glass.  Hard as a rock.

Patrick Hayes
Fremont CA

Same results with the tank of my Gravely tractor done about the same length of time ago.

[canuck750]

This may be worth a try, available from Bumper to Bumper in Canada.

[Kiwi_Roy]

Jim, that would probably be ok to seal a visible leak but I already have the Caswell.
I hope it will seal the tank without destroying the paintwork.
Thought I might drop an old EV tank on there for a while so I don't have to rush the job.

[canuck750]

The original gas tank on my 72 Eldorado had some body filler on it and it had a liner installed by the previous owner. I had the gas tank repainted and after I started to ride it I noticed a pin hole leak under it. I tried patching it with an epoxy several times, picking away at the pin hole / blister under the tank. Eventually I gave up and sent the tank to a professional paint stripper here in town who has a giant tank that takes an entire car.

This is what came back, more holes than I could count, the paint, bondo, tank liner was just barley sealing some of the holes.



I then tried cutting out the bottom and welding in a patch panel on each side, the original tank metal was so thin I just kept burning through as I tried to patch.

In the end I bought a good rust free gas tank from Mark Ethridge at Moto Guzzi Classics and had it repainted.

[bigbikerrick]

A friend of mine had good results with a leaky white float, by coating it with a 2 part clear epoxy. he checked it 2 years later, and it was still sealed perfectly. I think he mentioned he used "3 Bond epoxy" he "painted the outside of the float with a small paintbrush , and let it cure for a couple of days before exposing it to gas.
Good Luck,
Rick.

[Antietam Classic Cycle]

The original gas tank on my 72 Eldorado had some body filler on it and it had a liner installed by the previous owner. I had the gas tank repainted and after I started to ride it I noticed a pin hole leak under it. I tried patching it with an epoxy several times, picking away at the pin hole / blister under the tank. Eventually I gave up and sent the tank to a professional paint stripper here in town who has a giant tank that takes an entire car.

This is what came back, more holes than I could count, the paint, bondo, tank liner was just barley sealing some of the holes.



I then tried cutting out the bottom and welding in a patch panel on each side, the original tank metal was so thin I just kept burning through as I tried to patch.

In the end I bought a good rust free gas tank from Mark Ethridge at Moto Guzzi Classics and had it repainted.

The front curves of one of my tanks looked like that - must have been hanging up, front end down, for quite some time. Mark called it a "pasta strainer" and sold me another that was already chromed and primed, ready to paint.

[normzone]

The original gas tank on my 72 Eldorado had some body filler on it and it had a liner installed by the previous owner. I had the gas tank repainted and after I started to ride it I noticed a pin hole leak under it. I tried patching it with an epoxy several times, picking away at the pin hole / blister under the tank. Eventually I gave up and sent the tank to a professional paint stripper here in town who has a giant tank that takes an entire car.

This is what came back, more holes than I could count, the paint, bondo, tank liner was just barley sealing some of the holes.
 
I then tried cutting out the bottom and welding in a patch panel on each side, the original tank metal was so thin I just kept burning through as I tried to patch.

In the end I bought a good rust free gas tank from Mark Ethridge at Moto Guzzi Classics and had it repainted.

That's a truly impressive image - you could have re-plumbed it and used it for a lawn sprinkler or a shower head.

[Kiwi_Roy]

Made some progress tonight, drained all the gas, filled all my tanks and had to give a couple of gallons to Carmine next door, he always admires my Guzzis

Swilled a can of Acetone around then washed it out with hot water and detergent, all the smell has gone.
Dried it by poking the hot air gun in the filler hole on low setting, that got it pretty hot.

I decided not to do the drywall screw treatment, when I first rebuilt the bike I used rust mort, i don't see signs of rust.

Wondering what I could plug the petcock holes with, I know, I'll shrink some heat shrink over the filter and use the petcock, then I can just slice it off later

Anything I have missed before swilling it with Caswell tomorrow?

[Lumpy Idle]

funny timing, last week i was just talking to a guy who owns an old honda cb350 about the same thing. i said that i really like caswell's and he said that he liked por-15. his technique (i thought this was good) for cleaning the interior was to put some vinegar and some nuts and bolts into the tank, seal it up, wrap it up in an old sleeping bag. and stuff it into a clothes dryer. he centered the sleeping bag (which was all bungie wrapped and then stuffed a bunch of other cloth into the dryer to keep the tank somewhat centered. then he let it spin with no heat, of course. he came back, drained it and flushed it, rinsed it, dried it and then used the por-15. he said it worked great.  my method was similar but instead of the dryer business i welded up a bracket for the tank and used an old BBQ rotisserie motor to spin the it slowly. that worked a treat too. then i used the caswells. caswells has worked well for me.

that picture of the swiss cheese tank is impressive. i had no idea they could get like that.

[tris]

................. wrap it up in an old sleeping bag. and stuff it into a clothes dryer. he centered the sleeping bag (which was all bungie wrapped and then stuffed a bunch of other cloth into the dryer to keep the tank somewhat centered. then he let it spin with no heat, of course. ................

... and I bet he only does that when he knows his wife is going to be out for the day 

[Kiwi_Roy]

I was going to use the POR15 product, I used their paint on the frame, made a great job, very hard almost mirror smooth finish nut don't get it on your hands.

The Caswell come highly recommended here.

2 cans in the package 8 oz A, 4 oz B so thats a no brainer

[Antietam Classic Cycle]

I'd recommend using the drywall screws - they're not so much for removing rust, but rather for "roughing up" the metal for better adhesion of the sealer.

I plug the petcock holes with rubber plugs (bought at Lowes), pour the sealer in through the filler, swirl the tank around without anything covering the filler (to better see that I'm covering everywhere) until I get to the point where I need to coat the inside top of the tank. Then I cover the filler with saran wrap held in place with a rubber band and swirl it around more.

Once I'm confident everywhere is coated, I pull the plugs and remove the saran wrap, let the tank drain over a trash can. As the sealer begins to set up, I use a knife to remove excess from the petcock bungs - I'll do this several times until no more drains down. Once it's cured, I use an M12-1.0 tap to clean the petcock bung threads.

[Lannis]

The original gas tank on my 72 Eldorado had some body filler on it and it had a liner installed by the previous owner. I had the gas tank repainted and after I started to ride it I noticed a pin hole leak under it. I tried patching it with an epoxy several times, picking away at the pin hole / blister under the tank. Eventually I gave up and sent the tank to a professional paint stripper here in town who has a giant tank that takes an entire car.

This is what came back, more holes than I could count, the paint, bondo, tank liner was just barley sealing some of the holes.



I then tried cutting out the bottom and welding in a patch panel on each side, the original tank metal was so thin I just kept burning through as I tried to patch.

In the end I bought a good rust free gas tank from Mark Ethridge at Moto Guzzi Classics and had it repainted.

I had a BSA Firebird tank that looked a lot like that when stripped, including some welded seams where a solder repair had been tried and couldn't be rewelded ...

I went to these guys:

http://www.gas-tank.com/motorcycle.htm

They cut the bottom out of the tank, replaced it, baked the whole thing in an oven, got the solder out of the seams, welded it back up, ground the welds down, primed it, and sealed the inside with some sort of red sealer that is holding up well over the years.   And it was like $325.

Lannis

[stick]

Roy,

Sorry to hear about your leak. 
If you do the drywall screw method, be sure to count the # of screws you put into the tank.  I did a 2001 Ducati 750ss tank for my Son (seam leak).  Put in 23 screws.  Retrieved  like 16 of them!   Took a lot of shaking and open-palm slapping to get the rest of them out.  One-by-one.

I used the clear Caswell coating, and it looks like a coating of glass inside. 

For corking up the lines and holes, I got creative with used neoprene gas lines, a champagne cork for the fuel level hole, stuff like that.  I left the filler hole open so I could see what I was coating.  Had a couple of drips from there, but nothing I wasn't prepared for (rags and acetone).

[Antietam Classic Cycle]

Using a telescoping magnet makes it a lot easier to fish all of the screws out. 

[stick]

These got jammed in places that you could not see.  Plus, steel tank likes the magnet, too.

As I said, "Count 'em b4 and after"!

[Sasquatch Jim]

 Best bet, don't stick pins in the tank.

[Kiwi_Roy]

Best bet, don't stick pins in the tank.

But how else do you keep the directions in place?

Rattled a few screws around last night, nothing significant came out.