Changing the Yamaha Rhinos wheel bearings is a real simple task if you have the right tools and a little mechanical ability.
Tools needed to change rear wheel bearings:
A socket to fit the lug-nuts (Could be lots of different sizes but mine are a 17mm) so you can remove the wheels.
1. A 32mm socket and impact wrench (fits the axle nut).
2. A 17mm+14mm socket and ratchet or wrench(fits the two bolts holding the spindle in place).
3. A blind bearing puller makes the removal of the bearings a lot easy and can be bought from Harbor freight for around 50$ (a 1" and a 1-1/4" wrench is required to tighten the blind bearing puller in the bearing) .
4. A vise or press (to hold the spindle while you remove the bearings).
5. A punch and hammer to lock the axle nut in place when re-installed.
A quick tip is to put the bearings in a freezer for several hours before beginning this process, metal shrinks when cold which makes them easier to press in the hub.
On the rear of a 450/660
First remove the wheel,
Next remove the axle nut,
next slide the hub off the axle,
next remove the two bolts holding the knuckle/spindle in place and the the knuckle should slide off the axle. It might be a good idea to put a little tape on the thrust cover seals to keep them in place.
Now you can proceed to removing the bearings. I recommend a Blind bearing puller for this task but it can be done a number of different ways. The main thing to remember here is to remove one bearing at a time from the inside out. Using the blind bearing puller slide it into one bearing and then tighten it on that bearing with a 1" and a 1-1/4" wrench. With the puller tightened in place you can either use a vise to hold the knuckle steady while you drive the bearing out with a punch and hammer or if you have a press you can simply use it to press the bearing out. When removing the first bearing remember to keep an eye on the spacer between the two bearings and don't loose it because you will need to re-install it later. The spacer will fall out with the first bearing. After one bearing is removed you can remove the other in the same manner from the other side. With both bearings removed clean the knuckle assembly and the the axle especially where the grease seals ride (trash/rust on the axle could cause the seals to leak causing premature failure of the bearings).
With everything clean you can begin putting everything back together by pressing in one of the bearings (either side which ever works best for you). With one bearing re-installed flip the knuckle over and re-install the spacer (I like to put a little grease on all sides of this spacer) that was originally between the two bearings and then press in the second bearing. With both bearings pressed in install the two wheel bearing seals making sure to put the correct one on the correct side. The outside diameter of these seals are the same but the inside diameters are different, an easy way to check and make sure you install them correctly is by sliding them on the axle and see which on fits correctly and install that one on the inside of the hub assembly then install the other seal on the opposite side of the hub.
With the knuckle assembly complete you can now install the knuckle on the bike in the reverse order of removal making sure to lock the axle nut in place with the punch/hammer and grease the two grease zerks before re-installing the wheel.
If you have any questions feel free to e-mail me firstname.lastname@example.org