A7 ST petrol tank leak - weld or tank sealer?

[Richard A]

Bike, just about to go back on the road after rebuild and find petrol now leaks from tank seam. Most frustrating.

Question is do I get the seams re-welded, or do I go for one of those seal repair kits. The weld will likely cause problems with the paintwork 

[Triton Thrasher]

As far as I'm concerned, tank liners/sealants are junk.

[JulianS]

My own experience is that sealants work with isolated  pin holes  but will not cure split seams or cracks or  holes or perforations.

[morris]

I had the (freshly painted) plunger tank leaking at the bottom seam. A mate, who is a professional welder, silver soldered it. It only required a (very) minor paint touch-up to have it as new again.
To be on the safe side, I sealed the inside but I have a feeling that wasn't really necessary.

[Black Sheep]

Check carefully which kit you choose. On other fora there are tales of freshly lined tanks failing, the lining coming off or turning to sludge. I had a leaky seam on my Velo tank which I repaired successfully with solder after the previous owner's attempt to line it failed.
Incidentally, I too have a leaky Star Twin tank - can't find the precise point it is leaking - but my bike is currently sporting a Gold Flash tank suitably painted. I like the 4 1/4 gallon capacity.
(See same reply on BSA Owners forum).

[Derby Rob]

I have just restored a suzuki x7 ( sorry guys) ,the fuel tank leaked in many places ,tried to tig weld it but it was just too thin ,like a couple of other post have said ,i found that silver solder was the only real repair option .

[KiwiGF]

I think this has come up before in other threads, my tank leaked from the front top and I used a small blow torch and soft solder to fix it, it's ok years later. The method is to get as thick as possible layer of solder stuck on over the leak, which means heating the tank and solder only just enough so the solder does not get too molten.

I did the same on the seam at the bottom of the oil tank, tho I had to redo that after a couple of years.

The damage to paint was minimal but could not be avoided....

There is a 2 pack epoxy glass fibre type product that might work....if it's out of sight. See:

http://www.selleys.co.nz/trade/specialist-products/epoxy-adhesives-fillers/knead-it-multi-purpose/

[duTch]

 I've used 'Liquid Steel' on a couple of leaks- one on the bottom of my Hilux tank, and the Beeza tank where the tap 'boss' cracked, and also some kinda hairline crack on  my Gutzzi tank, which I almost forgot about.

 I think it's also a Selley Product

[Seabee]

I have used Caswell Plating (two part epoxy) very successfully over the last 15 years. The Super Rocket has held up that entire time, even with ethanol laced fuel in it at all times!

[jachenbach]

Step one needs to be identifying the failure mode. Is it rusted inside? Was it running without the strap tying the two halves together on the bottom side? (don't know that to call it). Until the root cause is addressed, I think you'll likely see it fail again in the future.

[muskrat]

+1 for the Caswell. I've had good/fair results with POR15 but just did a carbon fiber "Duck" tank and it looks the goods.
Cheers

[Peter in Aus]

I use "Red-Kote" Fuel Tank Liner, works OK for me but the tank must be clean and dry, it took over a week to dry out so as no moisture could be seen seeping up from the seams.
Peter

[Joolstacho]

Tank 'liners' as they call them seem to work for some, but not for others. But when a chemical sealer fails you're left with an almost impossible problem of stripping it out.
-Silver solder, and bigger holes can be patched with copper sheet silver soldered on.

[Rex]

Soldering (preferably soft) is my preferred option, but I did another bike with POR 15 and I have to say it's really good.

[Bsareg]

Same here, POR15 was the first liner I had success with and still holding fuel