I have a 2004 yfz450 carb model and I have rebuilt the carb rejetted to 172 main and 48 Pilot. I have a slip on lexx mx no quite core. K&n air filter with out air box lid. Air/fuel is 2 1/4 out. Thinking I need to lower the leak jet size to 35 or smaller. Don't want to buy a quick shot. Other then the bog when trying to accelerate quickly it runs great.