Check to see if the plugs are wet. You said earlier that they smell like fuel, so it could be getting way too much. When i bought my ka-t it was unfinished and had been sitting for years. The injector o rings were bad and the pump was just forcing as much fuel into the cylinder as it could. This killed my pump and got gas in the oil. So, a few things you can do: check to see if the plugs are wet / blackened, (there could even be steam coming out of the plug hole when you remove them if there is a lot of fuel in there), open the oil cap on the valve cover and see if your oil smells like fuel, and see if there is fuel leaking into the cylinder during priming. You can get replacement injector o rings on
this page from deatschwerks.