I have a strange problem that just popped up last week on my 2011 WR450. When trying to accelerate from a low-mid RPM range, occasionally the motor will bog or sputter, and simply won't accelerate. It kind of feels like there's no spark, just kind of, but the motor will continue running (poorly) at the same RPM instead of revving. Quite frankly, this is a new problem I've never experienced, and I can't identify where it's coming from. Last year I put on the DrD Exhaust system, and removed the AIS and restrictive air snorkel. I didn't touch the gray wire because the power curve seemed perfect and didn't feel like it needed to be changed. I'm running between 200-600' elevation, but the humidity and temps have been increasing. Last weekend was the first time this problem occurred, and nothing has been changed on the bike in over 6 months. This issue seems to happen maybe once in every 10 hard accelerations, but more often when hot. I changed the leak jet to #40 this morning, put on an adjustable fuel mixture screw, and cleaned out the carb this morning... but the problem persists. Anyway, I'm at a loss here. Any suggestions pointing me the right direction to resolving this will be greatly appreciated!