Topic: Wheel Bearing Install

[mdl91881]

I'm putting new wheel bearing in the front and rear of my CB750.  I just have a question about the bearing spacer. How tight should the bearings be pushed up against the spacer?  I thought I remember reading that they should be tight enough to move up and down, but not side to side between the bearings.  Is this correct?

[70CB750]

Yes, that's about right.  If done correctly, the wheel will install without problems.

[chewbacca5000]

Here is how I do it.  I tap then check, tap and check each time making sure the sleve is not haging up.  Just put your finger in the bearing it should not be hanging up on the spacer sleeve.

Do the side with the retainer first and make sure that is it properly seated then do the other side.

[evanphi]

Here's my advice from my build thread (immortalized in the tips and tricks forum!)

The photos show a front hub, but a rear hub is the same concept.

Retainer-side first, using the old bearing to get it in place. Don't hammer the inner races!



Then put your retaining ring back on... and get the original stakes to line up. Make sure to punch new ones when you're finished!

Spacer... Make sure the NARROW END goes on the RETAINER SIDE. This photo shows the WIDE END.


Use the old bearing to get the new bearing to seat flush, to start.


NOW AN IMPORTANT PART.

Don't drive that bearing too tight! You want the inner spacer to be able to move, ever so slightly, but not too loose either!
The little sliver of silver you see in the center here is the opposite side's inner bearing race.


This means that the spacer moves, still (it was loose at this point). Notice in the pic above of the spacer that it isn't a super tight fit in the hub. It can move vertically (wheel upright as if on bike). You don't want it moving side to side, though, as that is too loose. It is all by feel...

How I found the magical "Just Right^TM" position for this floating bearing is that it should be tight enough so that the spacer doesn't move side to side (remember wheel in normal, riding position... up or down is OK), BUT you should be able to spin both bearings freely, in opposite directions, at the same time, independently of the spacer. You may find you can feel the inner race rub ever so slightly on the spacer at this point. It takes a bit of feeling around (use your pinky's, those are small holes on the front wheel!)... but you'll get it.

If you do make it too tight the first time around, GENTLY tap from the retainer side on the INNER RACES. GENTLY GOING SLOWLY, ALL THE WAY AROUND, WITH A BRASS PUNCH AT LEAST 1/4". Eventually you will get the floating bearing moved outwards a bit, and then you can try again. Ask me how I know... I thought I was done for, when I did it too tight... but I went and checked HondaMan's book, and this is what was recommended.

Then reassemble everything!

[slikwilli420]

The spacer does two things. It spaces the bearings so they don't pull into the inner part of the wheel and it prel-oads the inside of the bearing. Ideally the inner and outer race rotate on the same plane. You don't want there to be a bunch of pressure on one side of the inner race and none on the other as that will cause premature bearing wear.

[przjohn]

A little off topic but I would recommend lubing the new bearings too. It's an old dirt bike thing I learned awhile ago when, well, a long while ago.  We use a pick and pull one side seal off and put some good quality grease into one side only. If you pull a seal off a new bearing you will understand that there must be a terrible grease shortage in bearing land. By putting grease in one side only you are not over lubing the bearing and it will last many times longer than  a standard bearing. A decent 3 piece pick set is cheap money and a good investment for any shop.

[mdl91881]

Thanks guys! I got the front all done and back on the bike and everything is moving/spinning freely like it should!