ken oconnor and i seem to think that when slicks boy shattered a piston while on a ride with me on "awk mountain", it may have been due to shane crossing a very cold moutain stream a little too hard, splashing a large amount of water onto a very hot motor, causing the piston to shatter about 100 yards after the stream
the aluminum piston will cool quicker than the steel sleeve, causing piston slap, shattering it
same reason you let it warm up completely before riding it hard