I have an 05 WR450 and none of my current plug wrenches work. I have various wrenches that work for an XR 500, XR 600, XR 400, XR 650 and XT 600. I can't seem to make any wrench work on the WRF. I even had problems with a socket and extension. Has anyone found a wrench that works well and would be a good trail wrench also well? Does Yamaha sell a wrench for this bike? Thanks for your help.