Got a complete bottom end and cylinder head combination off the same low mile 09 TW. Thus far i am thinking I will build the 58mm crank kit and the yfm250 cylinder sleeved per. Sebastians list with the 74mm LA-Sleeve and the oem Yamaha 9.5 to 1 piston. Final bore still subject to change. I kind of like the 9.5 to 1 idea for not making it as fuel sensitive. Coach me on the best logic here based on experience.