when it comes to looking for bearing retrofits, the outer diameter and profile height of the bearings is what matters. if you go to pivot works website and search for the bearing application for your bmw. there should also be a specification for it somewhere, either listing the components of the kit including the bearing dimensions, or the bearing dimensions themselves.
now, go check for the same for whatever forks you are searching. if the profile height and outer diameters (both upper AND lower) match, then you are in bidness!
in some instances, the same bearing kit will work for several different forks ('frinstance, the xt600 i am restoring uses the exact kit that early 90s kx500s do, so that ended up being the front end i bought), so it's always a good idea to cross reference the kit number for your bike and see what else it is used in.
dealers are useless for this kind of info, because it involves a lot of back and forth cross referencing and may not always be absolutely clear. but with some digging on that one website, you should be able to figure this all out. good luck!
Originally Posted by drivenbydiscovery
thanks for that.
looking into it some more, i think the 2004+ Yamaha YZ bikes use the same bearings as the 2003 and older, so theoretically they should work. i actually stopped by a Yamaha dealer today but after posing this question, all i got was dumbfounded looks. so no help there.
only one way to find out i guess; buy a newer YZ triple tree with bearings and try to graft it on.
as one of my good mates always says; it's all just a matter of trial and error. with a little more error than trial.