diameter of 300ex stock headpipe

[Honda99_300ex]

does anyone know the diameter of a stock 300ex headpipe or the size of the gasket thats on the headpipe where it slips into the silencer.........thanks

[Regulator 250X]

The diameter of the majority of the head pipe is much smaller than where the pipe meets the silencer. My guess would be bout an inch and a quarter to inch and a half if that.....