Leaking Tank, Pin Hole / Rust

Put some petrol back in and look for a dark damp patch

 

That looks pretty bad to me, poke those scabs in the metal with a screwdriver and I bet they go through especially that dark looking one on the bottom right.

 

i think its a replacement tank, how long before it leaks elsewhere?

can it be repaired or welded with that por|?

 

I'd be looking at a replacement tank if that was mine.

I reckon your observations regarding fiberglass are correct. This is my guess:-
The tank has had some serious internal corrosion due to having water sat in it. This has resulted in numerous holes and thinning in the affected area.
Some bright spark has then built up the affected area internally with a fiberglass filler. (Isopon do one for body panel repair).
They have then used POR15, allowing an extra thick coating to set over the fiberglass (just to be sure .)

As the rust holes you are now revealing are on the visible curved part of the tank, a good cosmetic and structural repair by welding in new steel is economically not feasible, and you still have to remove the failed POR15.

 

I really think this tank is really beyond repair to a decent standard at reasonable cost by others. My guess is £100 to remove the Por, £200 for the welding, maybe £400 for the repaint?
In the same circumstances, I think I would look out for a barn find 600 or 750ss with a good tank, which normally means it will have been garaged since before alcohol was in petrol, as I think the smaller engines variants are silly cheap at the moment, swap the tanks over, sell the project on honestly declaring the rusty tank, and it is likely to only actually cost a couple of hundred difference.

 

I agree with the above probably, beyond repair. However I would say, many years ago the garage where I trained to be a motor vehicle mechanic had a large body repair shop. They often used to fill and smooth crumpled mild steel wings and doors etc with silver solder. This was before the days of generalised use of two part body fillers from a tin. I saw very high standard repairs that never cracked or shrunk like the early days using body fillers. Mind, there are many grades of solder and fluxes that were used. Probably a lost art now?

 

Don’t suppose this good person is in the Midlands? I also have a supersport tank that needs welding up.

 

As an aside (and small consolation, I appreciate) it's the classic location for the rust patch - i.e. at the bottom point of the tank on the side that the bike leans to when left (previously) on the side stand, where any moisture in the fuel will pool.

Lots of good advice here. (I would ask Geoff Baines who he uses for this sort of job, I bet he'll have someone.)

 

Try Dream Machine. As I said, mine had been declared as scrap. They worked wonders. If you're binning it, you've nothing to lose.

 

sorry, no he's South London way.

 

That’s a shame, people who can do decent repairs on tanks are few and far between, those who are reasonably priced even rarer!

 

Glad you are sorted, but please don't scrap the old one. There are precious few of these left and they can be repaired with work.

Stick it on eBay with a genuine description and you'll get more back to cover your new tank than you think.

I'd have a go at welding it up myself and might bid on it.

 

Yes deox C it.

 

The mess in the old tank was down to POR15 being used to fix the leak.
Once you have cleaned the inside seal it and you’ll. have a longer lasting job.