It starts as necessity - i seized my piston, carb fell out from connection so it goes very lean. To save money i decide to go for iron sleeve, so cylinder was bored and head was modified for yz144 piston. PV was trimmed be myself. It all cost me near 70$ + 92$ for piston with free shipping. I run only once, and can't really tell how good or bed it is, only two things that i can notice for now: 1. good pull from start on second gear - old 125 dont like to start from second gear at all. 2. wery good response from idle to max rpm. Also i got two plugs fouled real wet and oily - it running very rich from bottom, still have to mess with jetting. View: https://youtu.be/F2fVxwgdkuI View: https://youtu.be/UomconPwd1U I want to thank all who answered me on forum, especially to Walt http://www.cafehusky.com/members/wallybean.586/ without you this wouldn't be possible!