Hello, I am having some probs with my 99' 400. It pops, won't idle, etc. I have changed about all the parts in the carb (the float needle & seat, accel pump gaskets / diaphram, gaskets, etc.) with no improvement. If I bolt on my buds 426 carb...It runs like NEW. REALLY STRANGE...Bought it from a guy who claimed the carb needed cleaning and he never messed with the carb...I checked the valves...Perfect. Compression is fine as well. What is the float level setting????? Maybe that's the prob. Any other base settings for a stock bike with the airbox lid removed? Pilot / main sizes? I live in Florida. This is KILLING me...Some have posted the slide could be a problem...Could that cause my problems? The bike WILL NOT idle at all...Doesn't matter if you crank the idle screw all the way up either...Pops like crazy too... Again, the bike is PERFECT with a stock 426 carb bolted on...&%$#@!? THANKS FOR THE ADVICE!!!!!!!