goosedog: I have an 01 YZ-426. Last year I installed the 12oz. stealthy and just love the difference. Boyd When installing the Steahly, do you have to pull off the OEM flywheel with a flywheel puller or do you just have to thread it on. I'm asking cause I believe I'll get one and want to know if I can do the install or if I should figure the added cost of my mechanics time as well.