I have a Full Factory 4.1ti exhaust (powerbomb header), twin air air filter, and just bought a Dyno Jet Stage 1. I put in the jet kit with the provided instructions, Took it out for a quick ride to see how it ran. Bike runs fine just a lil pop on decel. I put the bike in my garage and went to eat. Came back an noticed a milky colored substance coming from the valve cover breather tube. I know its not good to have that color coming out of an engine. Heres the Jet Specs. Main Jet - 160 Fuel Needle - 3rd groove. fuel screw 2 1/2 turns out the kit comes with a 165 main jet. 160 sounds a lil lean but it was the suggested jet for my mods/elevation Seems like water in the oil. I just bought the bike less than a month ago so I dont think the water pump seal/propeller would be the cause.