I have a KFX 400 Kawasaki and it is stalling when I down shift and hit the gas. I have to switch the tank to prime and put on the choke to start it again. I called the dealer and he said it was a clogged jet in the carb from bad gas. Does cloged jets sound like it could be the problem? I use good high octane gas. I do not have any mods and I ride at least every couple of weeks. Would some gas additive from a auto parts store help? They want $68 to clean the jets.