Rusty tank letting rust through, causing occasional blockages

Hi

Got a slight issue with my KZ440. There is rust in the tank. Not much, but it's there. The fuel tap has a filter screen, and I'm running an inline fuel filter (new). However, the rust particles are getting past the filter (I think they're just being broken down smaller and smaller), ending up in fuel line. Of course, it ends up in the carb as well, but I think the main issue is where the fuel line enters the carb. When I detach the fuel line, it has very fine sand-like rust particles inside. Before the fuel line: no rust particles. After the fuel line: tiny rust particles slowing down the carb refilling. That's why I think the fuel is just dissolving and making the rust particles smaller so it gets through the inline filter. You can look at the fuel filter and see it's catching no rust - there is no brown there. 

The bike is otherwise working fine, but after a certain number of miles after cleaning the fuel line and carb, it will be starved of fuel and will cut out. Then I have to pause for a few minutes while fuel trickles through. The distance I can travel before the clogging effect occurs is increasing, i.e. it seems to be getting better. Once it's clogged, I have to make frequent pauses while it tops up. So the past few journeys have been like this:

Do you think I could get away with a few more tank refills, i.e. will this eventually flush it all out? Or should I bite the bullet and seal the tank?

Best thing, is derust the tank.  For light rust like you describe, I'd use Evaporust.  You should remove the petcock, a fuel sending unit, if so equipped, and anything else that can get damaged during the derusting process. Fabricate plugs for any openings.  Harbor Freight sells Evaporust for a decent price.  One gallon will work, as long as you are willing to pick up and shake, and rotate the tank, so all the surface area stays wet with the sauce for a day or two.  Two gallons is better, though, and you can save the solution when done for future use.

After the rust is gone, dump out the Evaporust into a tub for reuse.  Use a garden hose, or your bathtub to rinse out the inside.  Have a can of WD-40 at the ready as soon as you rinse out the tank, and spray the crap out of the inside as soon as the water is all drained out.  Spray HEAVY, and swish around the solution to get all the inside surfaces of the tank coated. WD = Water Dispersant.  This will help the tank dry out without flash rusting.  A hair drier, aimed at the tank opening, will help dry the tank also.  Take your time and do a proper derusting job, and you will reap the benefits for years to come.  There is no need to coat the tank with a liner unless the inside is very heavily rusted.

If the tank isn't leaking you don't need sealer.
Just de rust the tank.

We use EvapoRust all of the time. We skip the water rinse and rinse with a gallon of diesel. Put in the diesel and shake the crap out of it. Pour the diesel into a clear gallon jug and watch the sludge settle. After it settles pour the good diesel back in for another round and dump the sludge. Do this a few times and it should be done. It won't flash rust and the diesel residue won't hurt a thing when you fill up with gas and ride it.
We buy 5 gallon buckets because you can use it over again a bunch of times on other rusty parts before it goes bad.