My buddy has his YFZ and he is trying to make it a little faster. It has a +3mm stroker crank and DG exhaust. Not the best Exhaust but he already has it. I know he needs a piston as it has a ton of hours on it he is just trying to keep up a little better and realized that his YFZ needs some freshing up after this weekend. I got him talked into a Piston for right now. He don't have a big budget to work with. Can you bore YFZ cylinders or are they plated.