The Bolt(6x20) is the most widely applied product in the GSXR1000Z 2004 (K4) USA (E03) OIL COOLER ( four times ).
A sample from the products for the Oil Cooler include: Bracket,oil Cooler, Bolt(6x20), O Ring(d:2.4,id:11.8), Bolt(6x16).
Check out any of the fourteen Oil Cooler components enlisted.