these are the ones i bought
http://www.ebay.com/itm/LB05E-NGK-2-Quanity-Spark-Plug-Caps-Yamaha-5k-ohm-WR500-IT-YZ-490-DT-IT-400-425-/130815900825?pt=Motorcycles_Parts_Accessories&hash=item1e753c3c99&vxp=mtr
you can save some money by buying used from the classified if you're patient. havent seen many sb inframes for sale lately though. might just have to bite the bullet and buy new.