They make a race bearing for minarelli engines for $50 it creates more stall speed without stressing out the spring so i took a construction washer 1-3/4 Id x 1/8 and it worked sort of? i need allumimum washers but they are hard to find, hate to spend $50 on my stock italjet, you can due the same for a honda= its an old school trick, glad i thought of it = my brain still works