I got a 2004 400ex for 1200 this morning! Had to cross to another state but was worth it in my opinion. Has a full CT racing exhaust and header, nerfs, kfx 450 front shocks, and it starts right up with the choke. But when I take the choke off and keep it revving there is no issue. The problem is when I’m downshifting or just pull the clutch in while slowing down the engine cuts off. And also the carb leaks gas when the bike is off. I know the carb needs to be rebuilt or cleaned since the guy I bought it from said it’s been sitting for years. So what I’m thinking is take the carb apart and soak it in carb cleaner, really clean all the jets, get it sparkling and also maybe chance the pitcock O-ring since when I turn the fuel gauge to “off” it still leaks gas. I think this is a good place to start what do you guys think... and also when I’m hitting the gas hard and banging through the gears she pulls nice and hard so I think it’s a minor issue.. thanks!