Not to jump ahead, and create trouble where there is none. Your supplier may have the 50mm piston in both wrist pin sizes. You will also want to open your main , and idle jets to get the new jug working right. I found torch tip cleaners work great. You can open the jets slightly until you get a good mix ratio, and not have a pocket full of extra useless jets. Hey man ps, I love the avatar. I tried to upload several animated avatars, and couldn't get them to run.