How do you change a water pump seal on a 1998 suzuki rm125 dirt bike?

You have to split the case on this year model. It is all internal, I have one in the shop now getting this done. The mechanic told me it is a real pain on this year model! Worst part is I just spent $1400 for this same mechanic to rebuild the emgine and do a big bore kit and he claims he replaced the seals during the rebuild.... Seems strange that the rdiator was dry when I got the bike with a blown motor and now it seems to be sucking water into the gear box. Only explanation is that it is coming from the water pump seal internally. Anyways on the 98 RM's it is a total tear down to replace the seal from what I am told.