Can I rejet the carb?
Rejetting is essential if you increase flow in the intake or exhaust. Dynojet makes a kit with an adjustable needle and several main jets. It also includes a drill bit for removing the pilot screw cover. A less expensive alternative is to use a KLX650R needle (N1TB #16009-1794), spacer (92143-1667) and clip (92037-1401), which which will give you an adjustable needle. You can then buy individual Kehin main jets to adjust the carb. A point of note: To remove the pilot screw cap, you must drill a hole in it. Drill very slowly, and pull back on the drill as soon as (or even before) you break through, so you don’t drive into the screw and damage it. You can also use a left-hand drill which will prevent you from accidentally driving the screw into its seat.
