Took my top end apart yesterday and found that my stock piston was cracked on the intake side :bang: I have less than 500 km on this new top end, so i would suggest to any one with any mods (pipe, reeds, etc) to be carefull. I know this has been posted before but i thought you could never have too many warnings. Just for your info i have used the stock piston before with the stock pipe and never had any problem until i upgraded my pipe and reeds. Glad i check my top end often, will have a wesico piston in it tommorow.