found a pinhole leak on my bike almost as soon as i got it and coated it with por 15 like many other people here. the coating is nice and thick, but the process does take time. give yourself about 5-6 hours to do the job from start to finish. 3 steps to the process: 1. clean up varnish with a bottle of 'marine clean' (1 - 12hrs) depending on how bad the residue is, 2. free up rust and etch the surface with a bottle of metal ready (1-2 hrs) and lastly 3. seal the tank (1-2hrs). the hardest part you'll find is getting the excess sealant out of the tank. take your time to do the job right with each step, since it's something you don't want to do again. you can also incorporate the tips that others swear by, eg - free up heavy rust by dropping nuts and bolts or sand into the tank and then shaking the hell out of it, use something like 'the works' (hydrochloric acid) or 'iron out', and then there's the electrolytic approach which is highly effective as well.
to save you some time, from what i've gleaned after reading through the posts on this board, i've learned that: kreem is a disaster and tends to break up after some time no matter how carefully it's been applied. red-kote might also be ok, tends to be the brand that radiator shops use, but it's not easy to find. that's another option if you want to avoid the work. find a radiator shop that seals tanks; a lot of them do it and the cost will probably be somewhere between what you'd pay for the por 15 kit and buying that tank you saw.
most people here are diy'ers, so you'll probably get the suggestion that you do exactly that: diy. good luck.
