Is it possible to renew the eccentric shaft bearings without special tools
Which ones? The ones in the stationary gears? You SHOULD use a press. Im sure there is a way to do it without one (mazda manual states to use the factory service tool and a hammer :S) but i always say use a press.
If your talking about the pilot bearing (the little one inside the eccentric shaft that the gearbox input shaft slides into) then yes. Very carefully with a dremel grinding disc.
Cant think of any other bearings you could mean..
Yes the stationary gears, thanks for info