Had a long nice trip (totally about 500 kms) but the first part of it was under heavy rain and I had to refuel at unknown gas station. Nevertheless had no problems. After I came back, started to suffer from sputtering - the engine dies out especially if there are high rps on the 1st, 2nd and 3rd gear and almost every time when the bike comes across and "jumps" gettin over some minor bumps or "buried cops" whatever the speed and the gears are. After that I can start the engine again - though not immediately but in a minute or two. Please advise me where to look for the trouble - I have no idea in which part of the fuel line! Otherwise cannot travel in the heavy traffic - just unsafe. I have a nice ZX-636A1 of the year 2002. Thank you.