i have a 1993 KDX125SR and have a question about the reed valves, there is a yellow plastic block inserted between the valves themselves and the inlet hose, it fits into the structure, anyway is this there too de restrict power or detune it? in other words is it safe to take that out and will it increase performance.
It's there to help concentrate and guide the flow of air/fuel into the cylinder. No, I do not think there would be any performance increase from removing it.