The job turned out to be easier than I expected. I used a piece of 3/4" pipe to drive the races out - the lip on the pipe worked better than the long punch I was using, which kept slipping off. The hardest part was getting the bearing off of the steering stem. I heated up the bearing with a propane torch, then just drove it off. To put the new bearing on the stem, I used another piece of pipe that fit the inner race of the bearing. I place the lower triple clamp on the floor (wood) and drove it on ( a press would have been easier but I don't have one). Note that if you buy new bearings, Yamaha has changed the upper bearing part #. The new bearing has a seal on it to help keep the water out, which toasted my original upper bearing.