I just did one tonight so I thought I would post a pic. Took a total of 5 minutes with common tools, and that included taking the shifter off. The hardest thing is finding a pipe that fits the seal face. Steps:
1. Take of shifter and lay bike on it side
2. Using an awl or other sharp pointy thing, poke a hole in the metal face of the seal.
3. Screw any type of small wood/metal screw into the hole and clamp a vise grip to the screw.
4. Tug on the vise grip and the seal pops out. Sometimes a large screwdriver can be used to lever against something to apply force to the vise grip.
5. Clean out the seal pocket and slide the new seal onto the shift shaft.
6. Using a pipe tap the seal into place. Install the shifter and you are good to go.
As usual, the pic tells the whole story (note: I should have used a smaller screw). Cam.
