[kz1000st]

You still have to break in the new barrel and piston/rings. That is another 300 to 1000 miles before it's all seated in. Believe me when I tell you these GY6 engines take a while to become fully broken in. My 150cc scooter is not the same now as it was when it had 1,000 miles, or another 3,000 miles or yet another 3,000 miles. Patience is the buzzword with these motors. You can bore them out, change the gearing and maybe get them up to 55 mph-once.

After that you'll be rebuilding, replacing parts and fixing for a long time. Seriously, if you need 55 mph an 80cc scooter is not the way to go. Even a 150 is starting to breathe hard at that speed. Think motorcycle or 250cc scooter.