I have a 2005 Honda Rubi with appox 350 miles on it. After the bike had been rode hard on a hill or in the mud it will start stuttering. What I mean by that is it is running, but its like it will not take any fuel. You try to give it fuel it just spits and sputters. It has been doig this for a while. Its almost like its getting vapor liked. This often happens after the engine has been stalled out. Does anybody know what would be causeing this? I first thought the carb was turned up to high, so I slowed it down a bit, but that did not fix the problem either.

 

Sounds like a fuel issue to me. Water in fuel or carb bowl would do this, as well as a fuel obstruction or float level problem (like having it in ON instead of RES when you're low on gas, but I bet you've checked that). Try draining the carb into a clear glass or plastic jar and see what it looks like. Any water will separate from the fuel, but a gummed up float valve may not show by doing this.

I'd start with fresh fuel too.

 

In order to test for a sticking float or a seized needle in the bowl, you can open the drain for the float bowl on the carburetor. With it open, turn the gas on. The gas should coninually drain out of the bowl if all is working as it should. If no gas drains from the bowl or very little, chances are your needle is dirty or rusty (from water in the fuel) and it won't open completely (if at all). The fix would be to take the carb apart and clean it. I'd also replace the needle.