WHite Brother Pipe/ K&N/ Jetted/ Black Box/Stage 2 Cam/ 11:1 piston stock bore to save on heat/ Head Flowed Ported Polished-Exhaust Shorter Bronze Guides Race Springs quad valve shaved/ Head was quenched, 11:1 piston was installed but after the quench bumped the compression to 13:1 the top of the piston as well was polished....all honda 400ex riders the piston to head clearence you will be surprised what Honda left and allowed, much room for impovement and HP.

 

Do you still own your 400ex?