Honda TRX Any info on tc505 or fst500 big bore kits for 400ex? December 3, 2015 Does anyone on here run these? Mickey dunlaps fst500 kit claims to be as reliable as stock with the lighter than stock piston, and probably other things I just dont know anything about them. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related