My bike runs good except when I snap the throttle open real quick the bike will stall. I was told that this is a characteristic trait of all 4-strokes. Is this true? Does anyone have any sugestions? Thanks 99 WR400, airbox lid removed, throttle stop trimmed, WB Pro Meg & tapered head pipe w/9 disks, YZ timing, DVP needle #4 clip, 178 main jet, 48 pilot jet, #200 main air jet, Sudco pilot air jet screw 1 1/2 turns out, pilot screw 1/2 to 2 1/2 turns out; no improvement.