Originally Posted by Kioshk
Welcome! Soooo...what's all this about a 4-leaf-clover pattern?
yes you know you can grind ramps in the piston right ? well grinding the exhaust and intake ramps as well as the transfer ports makes sort of a four leaf clover pattern in the pston dome if you have the domed piston and not the flat one . when you look down at the top of the piston the ramps form a 4 leaf clover pattern in the piston dome . only the tranfer ports are smaller than the exhaust and intake but it still looks like a clover.
this mod gave me a lot quiker rev's and a lot more take off power and a wider power band by effectively changing the port timing without having to raise the jug by 1mm or more and then have to mill it down and raise the exhaust port. cutting the piston skirt is almost the same effect as owwering the intake port by 1mm and the ramp on the intake side allows the charge to come in faster and easyer . the transfer port ramps change the tranfer port timing by the amount milled down into the piston rim so if you cut a ramp .5mm down the rim it raises the port timing by .5 . cut into the rim .5 as wide as the port opening and bring it up to the center of the piston in a triangle shape of course the wide end of the triangle being the port opning and the point being the middle of the dome, if you do this for all the ports you have effectivly raised them by .5 and now have what looks like a clover pattern in your piston dome.