I've been hearing alot about opening up the airbox on the klx110. I drilled some holes in the upper portion prior to passing through the filter. I do not recomend this. The engine flutters when given throttle and dosen't idle well. I was going to jet the carb up, but after talking to Powroll, I learned that the stock airbox actually has the best overall performance on the dyno. There are other mods for the air cleaner, such as a K&N air filter, but bottom end is sacrificed for more top end.