Originally Posted by SCouch
Finally getting exhaust, high flow filter and jet kit for the 2001 KLR 650. I've seen some suggestions about drilling holes in the airbox to create air flow, but I'm thinking this will let water in. Is there a way to increase air flow without causing water problems, or is it even needed?
Yes and no.
Yes: the way around it is to cut an "L" in the top of the airbox. You can use a die grinder / Dremel tool to cut it with an abrasive wheel, go slow and you can do a very fine job.
From here: Link
No: It's not necessary in my opinion.
Unless you do other mods like a 685 kit and a big valve head, and what kind of dummy would do that to a KLR.