My motorcycle will start and idle with ease, but as soon as I give it a little throttle, the engine bogs down (stumbles/misses, not sure of the correct terminology). Most of the time, I can ease it through the bog until I get to higher RPMs (2000+) and it seems to run fine. However, sometimes, the engine will stall during that initial throttle. What is this indicative of? Mechanical wise, everything is stock (air filters, exhaust, etc.) I'm a newbie and not sure where to start looking. Is this an air leak around the carb intake boots? Is this due to dirty carbs? Please point me in the right direction. Thanks!!!!