okay, so where not actually dealing with a Minarelli but a Carabela. The engines are nearly identical except for the fact that the transfers on the Carabela case are too big to accept a Minarelli kit. My cylinder is badly worn with a nasty ridge in it, so it needs to be bored. Looking at pistons from Handybikes, I would end up paying the same amount for a a 43mm as a standard size piston, bringing me to a blistering 61cc. Is this too much to over-bore a Minarelli cylinder? the cylinder is cast iron and the walls seem very thick, and after the boring would still be thicker than what I've see on many kits. Has anyone done this before?