First off, better pictures and tutorial here BUT its not in english but still very valid.
Here is a discussion on the subject: Hobbit - Final Drive Disassembly
This is a quick overview on how to take a Honda PA50 or PA50 II final drive apart.
Skill level required - 3/10 Tools required - Nothing special 14mm wrench (oil drain plug) 10 or 12mm for selector arm screwdriver with JIS bit or #3 Mallet Vice Torch (Bearing removal)
You have to remove the rear wheel from the hobbit subframe
4 bolts on final drive ( 2 have nuts, 2 have them built into the rear drive ) remove the tensioner for the chain, remove the belt
Now you have a big wheel with the final drive. Hammer on that 7/8 12pt socket impact it off with hand on the wheel / rim. slide the break hub off, now your getting there.
Drain the oil by removing the 14mm bolt in the middle of the housing.
You also need to remove the rear pulley. I would use a strap wrench on the thing or an impact and then the correct threaded puller so you don't bend the pulley.
Now unscrew the 5 JIS screws. I used my craftsman screwdriver to take off the screws. The bit was a #3 Phillips though. I had to use the blk wrench to get torque on it! Impact driver would be ideal
Now you need to separate the halves. To crack it apart, you gotta hit it. Maybe rubber mallet. A few smacks with some firewood worked for me. Clamped it in a vice on one of the bolt tabs and rocked the case back and fourth a few times and had no problems.
So with the two halves there is a couple of washers to take note of. There are a few shafts & gears that sit in their own spaces! Very important to place them back correctly.
So at this point you may as well remove the bearings and replace them. Its cool with me! Heat up the inside, or outside of the case, smack them to the inside, done.
Picture of the tricky output shaft assembly
Cleaned up cases
2 x Small washer @ .95mm thick, OD 18.6, ID 10.34
1 x Large Washer @ .98mm thick, OD 27.92, ID 17.16
These are the Honda OEM parts for the seals and bearings. Yours may or may not need replaced. Check your local honda dealer for bearings, or order them yourself from a trustworthy shop. Oil seal dimensions are in metric (e.g. "24X34X5.5" means 24mm inner diameter, 34mm outer diameter, 5.5mm thick)
For the pulley side,
BEARING (6201) 96100-62010-00 OIL SEAL (12X22X5) 91201-965-000
For the brake side,
BEARING (6203) 96100-62033-00 OIL SEAL (24X34X5.5) 91203-148-003
There are two of these needle bearings on the gearshafts:
BEARING (1010) 91021-148-004