One more time, 90-06 yamaha blaster lower ball joints are taper seat joints (the part that sticks into the spindle is cone shaped and there is a cone shaped hole in the spindle)
90-06 yamaha blaster upper ball joints are "pinch bolt' style which means they're a straight 14mm shank with a divot cut in them and then the spindle has a slit on the back of the "socket" and a bolt that passes through the divot.
Grizzly lower ball joints are a replaceable version of the blaster upper ball joint. If you have a 1988 or 1989 blaster, it uses pinch bolt style upper and lower ball joints so grizzly ball joints and a "ring mount" would work well.
Otherwise you have to have a "yamaha taper" ball joint and there are none available better than the Ricky Stator 16mm shank ball joint.