CB550 Petrol tank leaking - hairline opening worn in the under side

[zebedee85]

Hi all - I'm having a horrible morning - opened garage to find petrol smell and fuel dripping from the bike. I have the tank off and it looks like a badky placed wiring loom cable tie has worn a groove in the under side, and it is seeping from there.

Any ideas on repair? I finding a replacement tank is likely going to be impossible.

[Trigger]

Find a good old welder, as it is on the underside it should be a easy repair.

[AshimotoK0]

Find a good old welder, as it is on the underside it should be a easy repair.

How do you do that without guaranteeing this doesn't happen? Any ideas?

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[Trigger]

The old myth then Ash,
Drain the tank, leave it a couple of days to air the fumes, wash out with diesel. Petrol on its own doesn't catch alight, the fumes do  

[AshimotoK0]

The old myth then Ash,
Drain the tank, leave it a couple of days to air the fumes, wash out with diesel. Petrol on its own doesn't catch alight, the fumes do

I thought when you emptied a tank you would have fumes left  ....Problem with diesel is I think   it would be it would contaminate the weld. Heard of people filling with water but that causes flash rusting .. maybe a swill with DeoxC after flushing.

[AshimotoK0]

I got some mega cheap silver content braze off eBay last year  from a guy who used it for repairing fridges. Beauty of it is it brazes easily with a Mapp gas burner. Wish I had bought more as he's sold out now . It was square section about 3mm. Perfect for tank repairs.

[hairygit]

The old myth then Ash,
Drain the tank, leave it a couple of days to air the fumes, wash out with diesel. Petrol on its own doesn't catch alight, the fumes do

I thought when you emptied a tank you would have fumes left  ....Problem with diesel is I think   it would be it would contaminate the weld. Heard of people filling with water but that causes flash rusting .. maybe a swill with DeoxC after flushing.

I done a couple of Landrover petrol tanks years ago, left it empty for a couple of days, the pumped a load of CO2 into it (had a large bottle attached to the mig welder) theory being the CO2 displaces any residual petrol fumes. Certainly worked, no scary moments welding them.

[mike the bike]

I brazed up a Ford Escort III tank.  I just flushed out the tank with hot water and detergent and it was OK.  More steam than petrol fumes.  Brazing is preferable because of the lower temperature involved which won't affect the paint if you're careful.

[zebedee85]

Thanks guys, you have given me some hope! I have spent a long time ironing out problems and getting the bike fully up to scratch, including a top end re-build and a subsequent change of rocker cover. I spent an hour tuning the carbs yesterday which went very well. It was only after I brimmed the tank for a long journey tomorrow (hah!) that the problem was exposed with petrol on the floor this morning, all a bit heartbreaking really.

Dave Clarke Motorcycles in Oxford recommended a good welder to me, waiting on them to call me back.

[K2-K6]

I've seen people doing "in the field" repairs on fuel tanks by emptying and then running a car exhaust into the tank to neutralise the vapour.

If it's near paint and risks heat transfer affecting the paint,  you can get heat absorbing putty to put on the paint to stop it going over temp. I've seen this done along a tank seam next to the paint without any paint discolouring.

It's quite common to repair classic car fuel tanks by using lead solder and maybe a patch if the tank is perforated. Someone in that field will have the confidence to work on it for you if you research in that direction.

[Tomb]

I've welded a few tanks, as said wash with soapy water does it. Heard of the hose pipe from running engine exhaust to purge the oxygen but never needed it.

[zebedee85]

Well - I took the tank to a recommended welder, having washed it out with soapy water and let it vent for a while.

They have blown it up. (the guy is ok, didn't check for fumes, didn't open the lid, didn't call me to ask for the key to open the top, just took a torch to it).


Obviously a new tank is going to be impossible to find.

What are my options - will a 400f tank fit? Are there tank fabricators who will make a one off? Has one of you got a tank in good nick? Do you know someone who might?

Absolutely gutted today.

[hairygit]

That is seriously bad news. Obviously not as competent as you were led to believe. Any welder who has a clue should have checked it before getting a welding torch anywhere near it. Are they a business? if so, they should have insurance to pay towards a replacement tank!

[zebedee85]

Yes they are a business, the guy had a tank blow up in his face, I didn't push the insurance question, but I did remonstrate on the safety checks. I will see him tomorrow. I wonder if it is possible that the under side of the tank could be cut out and new metal welded in.

[hairygit]

They have commited  a serious breach of health and safety by not ensuring the tank was clear of fumes and ruined a customer's tank as a result. Granted it probably scared the crap out of him, but they are legally liable for causing such damage, in spite of any verbal agreement. Personally I would push it to their insurers, and if they get funny about it, tell them you will report them for health and safety breaches, and mention it to the local fire station, they would take it VERY seriously, especially as there are compressed gases on the premises. Sounds harsh,  it you may have a hard time finding another half decent tank, and when you do, it won't be cheap.

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