I have a 2006 Special Edition YFZ450. It has a low-end bog when I come down hard from a jump or punch the throttle hard off the line. I’ve tried rejetting it and also tried the Boyesen Quick Shot Fuel Accelerator, but nothing seems to help. My dealer says the bog will always be there because it has a flat slide carb. What do you think is the problem? I don’t know what else to try. Thanks for your time.
My guess, son, is you are getting fuel slosh away from the jets during landing producing a lean bog, and you are punching the throttle too hard from idle and getting a rich bog. You should make sure your float level is at or above factory specs to minimize slosh and to roll on the throttle a bit easier from idle. Give the engine revs a chance to catch up with the throttle position.