Why?

Well, having done about 160 miles with no problems mechanically why would something so small cause so much hassle? Petrol tank leaks from the cap, new rubber seal, two rubber seals, new cap, new rubber seals (you getting the picture!) hammered it, bent it, cleaned it, swore at it ............... then ordered a new tank.
Reason, the old one has the bayonet fitting seems to be a bit notorious for leaking or hassle at least, or I could only put a gallon in and push it around right hand corners! cos it doesn't leak going around a left un!

But the real disappointment is I have had to go back to a sporty tank, so ordered the low tunnel "Frisco" style, which will change the overall style.. bugger! Also as I do not have welding gear it will cost almost the same as a new tank to get the old one modified with new cap and bung. Plus this one holds about a gallon more so I will at least get off my estate before I need to fill up!