ive run into the same problem. i have a r150 from a 94 surf which has the nut on the end of the shaft not the circlip. standard fifth gear teeth counts are 26t & 46t dyna gears are 23 & 49. i ordered dyna 5th gears from amayama, part numbers 33336-25030 (on mainshaft) and 33046-25030 (on ...