CR125 rear wheel bearing

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#1
All right i have a 2000 cr125 and just notice a little bit of wobble on my rear wheel. you can see that there is some free play where the axel is. so after doing some search on here i believe it may be the bearings. so my question is how do i get the old ones out and then put some new ones in.
 
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#2
You use a drift from the sprocket side to the brake side to knock the brake side bearing out. Use a drift to unscrew the retaining ring on the sprocket side. Knock the sprocket side bearings out from the brake side. Install is the reverse of installation. It is best to use a socket or piece of pipe that fits the outside diameter of the bearing. Never drive from the inside race. The retaining ring has to be replaced. There should be an aluminum sleeve in between the two bearings. I like to put a little grease on the inside of the hub and on the back side of the bearings to prevent corrosion. I coat the axle in anti-seize to keep it from corroding/getting stuck in the bearings. It would probably be wise to put a dab of grease or anti-seize on the threads of the retaining ring. It would be a good idea to replace the seals and collars, especially if the hub has been wobbling.

Whatever you do, don't ride the bike until you fix it. Bearings can fail catastrophically and destroy the hub which gets very expensive.
 
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#3
you will need a minimum of 4 items a propane torch, a long brass punch or rod, a hammer, a sponge or water spritzer, With the wheel off and sitting on top of a trash can first clean the area very well and remove the aluminum retaing ring with a drift. heat the hub only enough to get it warm use the water as a guide if the hub gets above the temperature of boiling water you can change the temper of the metal. when the hub is good and warm use the brass rod from the opposite side through the axle bolt hole and try to catch the bearing with the edge of the brass rod and tap it a little on each side to drive the bearing out even. remove the middle spacer. with the first bearing out drive out the other bearing. clean the hub and reheat it. Use your old bearings as a drift to tap in your new bearings this will protect your new bearings from any hammer damage. remember to evenly tap around to keep the bearing going in straight.

D
 

IndyMX

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#4
76GMC1500 said:
Use a drift to unscrew the retaining ring on the sprocket side.
Clarification, that retaining ring is on the brake side, not the sprocket side..
 
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#5
sounds like the apocalypse i have an old wheel lying around ill try tapping those ones out. if it kicks my butt i just may take it in. also would a socket work as a drift? or do you have any other suggestions that i may use.
 
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#6
It's been on the sprocket side on all of the CR250 hubs I've rebuilt. I've never had my hands on a 125, though. The microfilm says it's on the brake side so I guess that's where it is.

It's actually suprisingly easy to do the wheel bearings, there are just a lot of steps and a few precautions. Well, that is if the wheel bearings come out. I've never had them stick so I've never needed a torch (that would be bad anyways since the 1980's bikes had painted hubs). I did have a dealer split a hub on one of my Trail 90's while driving a bearing in. They probably had it in a hydraulic press and crushed it.
 

IndyMX

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#7
Also, I'd spend the few bucks required to buy the tool to remove that bearing retainer. I didn't when I did the bearings in my wheel. The new Pivot Works bearing kit came with a sweet red anodized retainer. Now it's all jimmied up from tightening it with a drift...
 
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#8
76GMC1500 said:
I've never had them stick so I've never needed a torch (that would be bad anyways since the 1980's bikes had painted hubs). I did have a dealer split a hub on one of my Trail 90's while driving a bearing in. They probably had it in a hydraulic press and crushed it.

ALWAYS heat your hubs when removing or replacing a bearing. The bearings are an interference fit. That means the bearing boss in the hub is smaller in diameter than the outside diameter of the bearing. When you heat the hub, it expands the aluminum and releases the grip on the bearing.

If you drive the bearing out or back in without using heat, it will remove a little material from the bearing boss. If you do this a few times it will wear the hub, your hub will be trash and the new bearings will be loose in the hub.

You don't have to heat it too much and it won't get hot enough to damage the paint on painted hubs if properly done. Just heat the bearing boss area using a circular motion and don't hold the torch on any one spot. Heat it until you can sizzle a drop of water or spit on the aluminum. The bearing should almost drop into the hub. It also helps to place the bearing in a plastic bag and put it in your freezer for a couple of hours. This will shrink the outside diameter of the bearing a little bit.

This is also the recommended procedure for replacing main bearings, gearbox bearings and other engine case bearings.

Or, you could just do what gmc does and get a bigger hammer. :(
 
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#9
I used the torch on my cases to do my main bearings and just let gravity do the work, I didn't even need a hammer. If I ever do need to get the bigger hammer, then I know something is wrong.
 
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#10
well i appreciate all the advice you guys have given me but before i go and order the bearing kit do you guys think this is what i need. again the problem is i have some free play where the axel is, a slight up and down wobble i guess would be a good way to describe it. all spokes are tight.
 
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#11
swingarm bearings, spokes, wheel bearings, could cause that problem. I also had a problem before where the hub was worn out not the bearings I had my local parts supplier knurl the inner hub (or whatever they do) to allow the bearings to be a interference fit like they are supposed to be

good save ol89er ALWAYS apply heat to press in anything and the freezer trick works great I use it for ring gears -put the pig in the cold and throw the ring gear in the hotsy works like a charm
 
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#12
richardhead84 said:
before i go and order the bearing kit do you guys think this is what i need. again the problem is i have some free play where the axel is, a slight up and down wobble

That is up to you to figure out. Remove the rear wheel and take the axle out. Take your finger and feel the inside race on the bearing for movement or roughness. If the bearing has any play in it or is rough when you rotate it, replace it.