Hi, first time posting. I have a 2004 Kawasaki KFX 400. When I give it gas I get the normal burst of power, then a second or two later there is a huge loss in power. This happens when the gas is in the "on" position, but not when I switch to reserve. Any ideas?

 

That is strange , my first thought was air filter but why would it do that only in the on position , Iv'e heard storys of the stem on the petcock breaking off in the gas tank breaking off , you could pull your petcock out of your tank and check it out.

 

There should be a screen on the petcock/onoff valve , the screen is on the on tube and probablly has trash obstructing the fuel flow ; the reserve tube doesn't have a screen only the on part of the valve has the screen !

If this is the problem after cleaning i would replace the rubber 'O' Ring and install a clear fuel filter in between the fuel hose ( between the petcock and carb ) , this will help prevent trash from entering the carb ; and you can see at a glance if trash or water gets in your fuel again !.....

 

when the problem occurs, does it only happen once or is it concitent until you put it in reverse