Geoff et al...
You do not need any special tools (presuming that OEM rollers are insitu), u will need Long drift punch to knock out the ball bearing outer cases from the head stock.
The outer taperred rollers are evenly tapped / hamered into where the outer roller cases came from.
The LOWER inner OEM case can be either ground off of chiseled (u need to really know how to chisel) from the lower triple clamp shaft...use a dremmel.
Then the new lower tappered roller bearing can be heated (GENTLE!!!), while the triple clamp has spent 40 minutes in the freezer...the new bearing will simply fall on with minimal effort...use a press only if u have the correct spacers so not to damage bearing...MOST important be sure the bearing is the right way round ie large side lowest.
Torque the same as for OEM, from memory 15 foot/lbs.
The top seal you remove does NOT go back.
U can get these bog stnd bearings from CBC...google for part numbers or I'll post em when l get home
Ciao the can :)