Shop › 1615 Bush 1″ Bore 5/16 Keyway Image 1 of 1 1615 Bush 1″ Bore 5/16 Keyway $38.50 Add To Cart Added! 1/4” Keyway1″ BoreSuitable for Honda GX630 engines or any engines with a 1” shaft. You Might Also Like Optibelt Omega HP 680-8M-50 $185.90 Tensioner Roller ONLY $119.90 Tensioner Arm and Roller $250.80 Omega Optibelt 800-8M-50 $218.90 HTD Timing Pulley 32-8M-50 $75.90