May I ask, what makes you ask those questions?
If you have access to a recnt model KX service manual, you will see a super expensive, specially shaped bearing puller for the bottom steering bearing. IF you didn't already know, the bearing is somewhat of a light press fit.
Something like this:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=3979
will not work, since it will not fit around the steering stops. Only a specially shaped puller will do.
If your lower bearing is shot, just use a Dremel (or similar rotary tool) and a small cut off wheel. BE CAREFUL to not cut into the steering stem.
You didn't mention WHY you want to take the lower steering bearing off, but if it is dirty, you won't gain ANYTHING by removing it. Just kill it with contact or brake cleaner and regrease. If it needs to be replaced, then just use the cut off wheel and be careful.
You CAN press the stem out to get the bearing off, but that is a bit extreme. :-)
Also, another comment based on too little info, you can get a new set of Pivotworks front wheel bearings and seals (two bearings and two seals) for $20 MSRP.
76, got any pictures of that 1987 Honda CR250R?! AWESOME!!