Petrol Leak

Don't know if this works, but permatex has been around a long time...

http://www.caswellplating.com/permatex/permrepairprods.html#gastank

I looooove Permatex, except when it was used last time.........

Dry it, then apply some Epoxy to cure ?

Polysulfide rubber is what was used to seal fuel tanks on military aircraft in the olden days when I was involved in such.

1. Polysulfide Rubber,Polysulfide Synthetic Rubber,Polysulfide ...
2. Polysulfide Rubbers

Teflon gasket can be used on gasoline pipe flanges.

Just use a TIG welder.

_{Yes, I'm joking!}

On a more serious note, let me ask a few clarifying questions.

What is leaking, gasoline or crankcase oil?

Have you identified the cause of the leak; scored gasket surfaces, stripped threads, pin hole in gas line near seal, other?

Is it under pressure? How much?

GA

My thoughts exactly.

O ring. At the pressure involved, a flange and an O ring should seal with hand tightness.

If the leak is from the threads, there are products made for sealing threads available everywhere. The petroleum industry here seems to favor a product from a company called Rectoseal. I usually use thread sealant with teflon from any recognizable manufacturer. Good luck.

No, no, no, nooo. Don't try to figure out where or how something has failed before you try to fix it. Just randomly change, hammer, torch, glue, weld, or machine any part you can reach. Eventually one will be forced to realize that entropy really does rule the universe. Without entropy and motorcycles that leak fuel, we may not have great scenes like this.

I forgot to mention that used chewing gum also works well at stopping aromatic hydrocarbons from leaking out of a fuel line.

That was me in the suit. I was afraid to get my hands dirty. (I was eating a burger)

I forgot to mention that used chewing gum also works well at stopping aromatic hydrocarbons from leaking out of a fuel line.

This is true, I used chewing gum to seal a hole in a petrol tank on a Mini until I got round to replacing the tank. I had to change the gum every week or so as it gradually dissolved.

Hermatite - assuming they still sell it.

Don't laugh, but I grew up with the sons of one of Westinghouse Electric's original Nuclear Physicists. Brilliant man, lacking in common sense, who passed some of those traits unto his sons.

Well, I had a 1950 Ford sedan with the flathead V-8 and my carburetor was acting up, so he decided to check it out.

While, talk about a high tech mechanic.

So, after disassembly, he discovered the float was leaking and proceeded to seal the tiny hole with Elmer's Glue. LOL.

Darn, it worked and I kept the car for another year in that condition before I traded up.

When I questioned him about Elmer's being water soluble, he said aha, but gasoline or petrol is not water.

Simple fix from the past, wonder if it would work today.

These floats were made of brass. by the way.

Maybe the original gasket was thick rubber/cork type that allowed an overtightened screw or two to deform either/both flange/s. Flatten flange and dry fit a new gasket with correct torque.

Why dry fit? I have NEVER seen gunk of any sort work well over time. How often did you try to seal a leaking windscreen rubber for example? A clean, gasket against a clean, flat and smooth surface works well.

Sounds like a missing/damaged gasket/o-ring problem to me.

Warped faces as suggested should be checked.

What has your friend tried so far?

There are loads of suitable sealers on the market.

I use Threebond 1104 for troublesome seals. Excellent success rates in universal applications and it is readily available and cheap.

The epoxy solution will work but has somewhat permanent properties and won't flex.

Its a gas leak, just treat it as if it were a BOP system or any other critical equipment and fix it. your balls are literally over IT for god sakes.

OK, some good ideas here, so just a clarification. This is a flange at the bottom of the tank where the electric fuel pump mounts. There are a number of bolts around the edge that have a torque setting of 3N/m, so not at all tight. The pump mounting face has a seal set in it that lines up well with the tank. The problem is that the tank is thin pressed steel and flexes, the retaining nuts on the tank are tack welded in place, badly, so will not take being used to well. These tanks are notoriously poor for this problem, but my colleague didn't know this when he changed the pump.

Is it possible to determine if it is the seal leaking, or the retaining nuts welded to the tank that have developed small cracks?

If it is the seal, a new one should be available, or perhaps shimming the old one with a fabricated brass shim.

If on the other hand, it is small cracks from the welded nuts, you already know the proper answer to that. The nuts might be able to be soldered with a flame-less soldering iron. Older heavy irons could transfer sufficient heat to overcome the steel tank's mass. Good luck.

Sounds to like a leaky petcock, damaged gasket or very brittle fuel hose to carb. Frirst try to replace the hose with new hose. If it is still leaking, there is compesion washer or gasket between the tank and petcock. Drain the fuel in the tank and remove and inspect the seal and petcock. The petcock are cheap to replace and would not even screw with it and just replace, you should get a new seal with the replacement. If it continues to leak you have a cracked fuel tank, check around the mounting flanges for cracks. Get it fixed or your freind may have a BBQ between his legs while driving down the road.

Nah, just slap some mud and goo around the area. As the OP pointed out, this is already a badly flawed design that everybody knows and accepts the piss poor quality. You cannot make a silk purse out of a sows ear.

Rip the engine out, remove all the fuel fro the tank and install a set of pedals.

Yep, problem solved.

Now there's a safer idea!

Hmm...a strangley attractive idea....

http://eclecticproducts.com/products/seal-all/

I've used this for years with great success (including 39 rusted out holes on a 1972 Datsun 710 fuel tank. (with roofing screws/washers))

WOW ok so we have all made (speaking nicely here) sub-standard repairs in our younger years, but really now... Is there any well founded reason why this cant be corrected PROPERLY so the poor fella doesn't catch fire going down the highway or while sitting at a traffic light eying up some cutie?

The correct fix would be to remove tank flush ALL fuel/residue and weld a solid flange to the stamped tin tank so the pump seal will do it's intended job. The OP wanted info an a sealer to do the same. I responded with a product I have personal knowledge of. It in no way implies that it is correct/acceptable repair. That is up to the OP to decide what is acceptable to him.

I do not find the most basic information in this thread....

What make and year of motorcycle is this?

Fuel pump???? Sounds like it must be fairly new.

My ole '50 Pan Head never had a fuel pump at all, so no problems there.

I did need to "borrow" some wiring from a hotels HVAC system late one night, but thats getting into electrical "rigging" and nothing to do with a fuel leak. Incidently I didnt vandalize on purpose I first begged them at the front desk to sell me an extension cord or anything they had, I think my long hair and beard at the time scared them to death, they politly asked me to leave there premises, so then a guys got to do what a guys got to do....

It's an '02 Suzuki, the fuel pump has to come off to clean the filter, there are no signs of damage to any part of the tank or pump seal, but as soon as petrol is put in the tank it starts to seep through.

Hummmm, we obviously some imperfection somewhere????? The only one (s) who can find it are you guys actually drinking beer in the garage.

No cracks+no scratches+good seals= no fuel leaks huh?

I'm afraid it's the old.."It's a common problem, mate, you need a new tank!"

Yeah, right.

So you have a long list of gooks that you can try, or you can replace the parts....

As Sean Connery said in the movie un-touchables, "what are YOU prepared to do?"

Install a a bolt with a nut in the mounting holes on the tank

tighten the nut against the tank flange

carefully tap on the head of the bolt until the area of the captured nut in the flange on the tank is slightly above the rest of the flange

this should allow the existing oring/gasket to work as designed

adding a homemade paper/cardboard gasket may not hurt either