Henry I had a similar problem - I don't think welding is the answer
CONSIDER - you have to dry the tank and vent it completely and keep it that way while you're welding and if there's any vapour around, well it's just BANG.
Also remember the leak is being caused because either the seam has blown, or there's some rust. I tried all sorts of epoxies etc on the outside, none worked because the leak is actuallt UNDER the bottom plate and you can't reach it !

You may like to consider coating the interior of your tank - there are a number of good products around - I had a guy do it for me a couple of years ago and I haven't looked back. If You do decide on this route, remember to shove a wire up the tank vent into the tank or you'll end up with a blockage (ask me how I know)

Gas Tank Sealer - Gas Tank Liner - Diesel Tank Sealer - Fiberglass Tank Sealer
there are many, here's one.

 

Blimey Mark,
you must have been making quite a roar for them to pull you up. I'd like to hear those little puppies in anger. Can you post up a Vid?
As for the welding offer, I'd so gladly take you up on it except for that damned pond thingy.
I see Pete's had something to say on this (I hoped he would) as a little birdie, well more of a Trout actually, told that he'd had the same problem.

Pete,
I tried petseal the first time I discovered the leak. Due to the amount of flexure between the tank and bracket this didn't last long. I think the stuff goes too hard to take that kind of treatment.
I'm very reluctant to put anything else in there as it's going to reduce the capacity of the tank still further and I'm not keen on that. The beauty of these beasts is a 22 litre capacity. Something that most modern bikes can only dream of. Given the mileage I do every week, this is a very important factor. I fill up every other day as it is, sometimes every day.
Thanks for posting up the links to the products though. I'll check em out but ultimately I think this is going to be a job for a specialist.
Did you know that you can add dry ice to a tank to drive out the oxygen while you're welding. A good idea methinks.

one nice little surprise today; My new Morgan carb sync tool arrived. Wonder what I'm going to be doing tomorrow afternoon after I get back from work?

 

You may laugh, but yesterday I was having a bit of a blap on the way home....
Just hit 12K RPM and **** knows what speed in 4th up a long straight hill and I thought the engine had blown it's head off, only to realise that the noise was a very loud guitar solo in my headphones. After the initial shock I pissed myself laughing, backed off the throttle and rode the rest of the journey home quite sedately, still laughing.
I mean....as if you could blow a Hurricane by simply pushing it to it's limits! Ridiculous idea.

 

holy crap, you actually rev it to 12k? i know it'll do it, but the bike falls on it's face past 10k so it's much better just to shift....

 

Finally pulled the trigger on a set of these for my 1990
fed up tucking my elbows in to see behind with the stockers

Full money back guarantee if they don't fit .... nope didn't pay
full $ either

 

Just got my new ignition in today, and installed it. I feel much better now that I can lock the forks.

 

Sprock,
if those were width adjustable on the hoof I might consider them but to be honest, I can see quite confidently out of my stock mirrors. Perhaps something to be said for being a mere stick insect.

 

Not so Bio.
The really juicy bit it right between 11 & 12 K. I see it as an occasional encore. If yours is falling flat after 10 then you've got issues fella!

 

Does this mean I can finally tell you to buzz off jk

Me no chance Henry om a big frigging lad - I am - the mirror on the 1990
gives me a great view of the vent zippers on my jacket and I have to lean
the bike to use the mirrors ....... so Im praying these will work.

Also my DanMoto 3D Adjustable bars came in for the 1993 today not
sure I like them they are a bit light and flimsy imo and one of them has
an issue , emailed Dan Dan to see what he's going to do about it.

Might have to turn them loose on Ebay ..... we'll see Dan Dan , I dealt with
a few times in e-mail seems a can do good type of Guy !

Also got my pipe bender and pipe expanders today ---- ready to get
custom link pipes on the go !

 

Hi,
just had my top end rebuilt with valves ported and re-ground and can vouch for the 10-12K power spike - its an awesomely quick rush that will catch a modern bike out
Bugkiller