I just recently bought and 01 yamaha wolverine, and it has a few problems that i need some help with.

The first problem is it needs rear differential bearings. The guy told me that there are 3 bearings that come in the kit. Is it hard to change the rear diff bearings or is it better to take it to a professional? The rear 4x4 is not working and he told me that was because of the bearings, so is that correct?

The second problem is it smokes when you full throttle it, and the guy told me it needs valve stem seals replaced. He informed me it was simple and just take the head off and you will see the seals and valve. Is the info he gave me correct? Also i was wondering if anyone knew where to get a repair manual online for free or do i have to buy one. Thanks for all your help and replies.

 

Do you mean axle bearings or diff bearings? The rear gearcase has 4 alltogether(3 are inside and hard to get to) I will explain... The diff bearings are fairly complicated without the right tools, you need to remove the differential from the swingarm and open up the case to get at them all. There is 1 in the front where the pinion rides on and 2 large ones for the ring gear, one on the inside and one on the gear case towards the outside. If this work has to be done then I would take it to a shop, they will need to set the gear lash properly with shims if new bearings are installed.
Now if you just need axle bearings there are only 2, and they are easy to replace, the one in the swingarm near the brakes can easily be punched out and the other in the diff case can be punched out from the opposite side.

I hope your axle splines are ok, the rear wheels should be turning with the front unless something let go, my axle splines on my wolverine wore out so bad the ring gear was spinning on the axle, I would check yours.

To better understand look up yamaha OEM parts and search for your ATV, they will give you parts diagrams, but no torque specs. You can get shop manuals from your local dealer or online from alot of places.

As for the smoke, it could be a couple things, does it smoke at a cold start-up? if so it's valve seals. No smoke at startup and at full throttle can be rings(costly)

 

If I understand you, the back tires do not turn? if so, the guy that sold it to you is a liar and a crook, sounds like a broken drive shaft or stripped out ring and pinion in the rear differetianl. Putting valve seals means having to remove the head, remove the valve springs, the seals press over the tube where the valve stem comes up from the combustion chamber, not a horrible job, but it means taking the top end off, and replacing the head gasket. Sounds like that quad was beat pretty damn bad to need all that work, my 95 has thousands of miles on it, been raced, duned, mudded, and never had to change out rear diff bearings, just the front crappy unsealed wheel bearings. To be honest, I would see about taking it back to the guy and getting your money back. Unless you plan on spending a bit of cash or learning to turn a wrench, sounds like a real "project" quad.

 

Thanks everyone for all the replies. I got the wrenches out today and removed the differential opened it up, and found the bearings just rolling around in the inside, there were little bearings just everywhere lol. The pinion gear was toast. That's why the rear 4x4 wasn't working. I could see the drive shaft turning but where it meets the diff is where it stoped turning so i knew something was wrong in there. Im going to the parts store tomorrow to buy the whole diff bearing set for like $69. I looked online and new diffs ready to install are like $700, so i think it will come out cheaper to buy the bearings and seals and take it to oriely and have them press them in. I also have to buy a new u joint for the rear which is cheap. I bought the bike knowing the problems it had. I bought the bike for $600 ,but he wanted $1500 so i think i still got a good deal. Thanks again for all the help and i will be posting the repair outcome. Until then ride hard and be safe.