I was obsessed with these things, and owned quite a few in the 80's and beyond.
My intro was the original BB1200. Massively built, big neck, reversed P-pickup, which was the Achilles' heel for some on these axes: They did not easily interchange with DiMarzio's or any other aftermarket pickup because of their different mounting ring system. Otherwise, a great P-Bass, and different than a Fender, gorgeous in that cherry over yellowed natural finish. Stout bridge, and the adjustable tension keys are fantastic IF you score the little spanner wrench you need to adjust their tension. All these axes ran a 33 7/8" (!!) scale, which with their pickups gave a more airy, not quite as dense a tone as most Fender pickups, great for recording. MIJ at Yamaha Music Craft.
The BB2000's were groundbreaking in that they were the first fully-realized P/J bass. Essentially built on the 1200 with the additional pickup, these were the s**t back in their day, and you saw lots of famous guys with brought-over-from-Japan examples (the decal says 'Broad Bass', a name never used by Yamaha in this country) in pics and on album covers. That blade pickup had a lot of talking to do, and these were great basses . . . except for some guys, it had a BIG neck, like the 1200. Which led to . . . . .
Yamaha in Cali was courting a famous bassist (you WOULD recognize the name) who liked the 2000 but raged about that thick neck and a few other fine points. This led to the BB3000 which to me is WAY better than 2000's, as the neck is just that much more useable, and they just look too cool with the brass pickup surrounds. They are a bit thinner back to front, so they're a little lighter, not a bad thing. BTW, said player over time wore out his welcome and the proposed signature model never appeared, but the changes he pushed resulted in the 3000. The orginal passives are fine, and the A models with active electronics (vol-bal-bass-treble) are good and sound somewhat EMG-ish. Of the fours, the BB3000's are the best.
These all ran the same wood recipe: Alder body wings glued to a maple/mahogany neckthru, with a thick Macassar ebony fingerboard, so they are zingier than darker. Yamaha was cool in that they didn't dye the fingerboards to all black, so most have that wonderful curvy chocolate stripe running thru the grain. Again, all of these MIJ by YMC.
And then, the BB5000. Essentially the 4-string BB3000 'subdivided' from four to five strings, same neck and fingerboard width, so it's a little tight at the nut end, not a big deal if you're used to Jazzes or Rics, but it can be a bit much for some. Yamaha added the original 3+2 P pickup (not adopted by the rest of the industry until recently), built a accompanying blade pickup at the bridge, added a 5-string bridge, and a 5th key on a slightly bigger headstock, and that was that. Same wood recipe as its' 4-string brothers, and essentially a BB3000 with one more string.
The 5000A1 was the second version, the bass above with the active electronics package of the 3000A with corresponding new active five-string pickups. MIJ.
The 5000A2 was a completely different animal. Made in the then-new Yamaha Taiwan factory (now closed, as they've moved all non-Japanese production to China), this was a different, bigger body, and previewed the electronics and pickups from the forthcoming TRB basses. Same wood recipe, but a bigger, different body, and a MUCH wider fingerboard (though the neck shape was fine, kinda flat oval). Still a fine bass, but for me it somehow lacked the gracefulness of the MIJ axes.
I owned all of these, and a 400 and a 1600, and my faves (by a lot) were the 3000A and the 5000A. Like all the Japanese makers, they abandon classics at a stupendous pace and throw something else against the wall to see what sticks, but I wonder what the hell they were smoking to think RBX's, Motion Basses, and TRB's were replacements for the BB's. Oh well . . . . . but I can tell you the ones they sell now as BB's are nice basses I suppose, but nothing at all like these.