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How to change your head bearings

59K views 68 replies 26 participants last post by  Sk8e_junkie 
#1 · (Edited)
I couldn't find a how to for this particular job so I thought I might put one together for you...

Well first question to answer is "How do I tell if I need to replace them?"

This is an easy thing to check, put your stand down and rock the weight of the bike onto it so that the front wheel comes off the ground, then move the bars from left to right. It should move smoothly through the full range, if you feel a notch anywhere (usually in the centre) then it's time for new bearings.

If you need to replace them, read on... and yes I know my bike needed a wash, I did that as soon as I had finished doing the bearings...

Getting the front off the ground:

First thing is to put the rear on a stand, then get a piece of wood to go under the headers and use a jack to lift the front end up, if you have frame sliders it would be a good idea to support the bike from those, exactly as I have done below.

Remove your front wheel:

Undo the mounting bolts for your brake callipers, remove them and hang them so that there is no weight being supported by the lines. DO NOT squeeze the brake lever once the calipers have been removed!

Next, undo the big bolt on the end of the axle then loosen the four pinch bolts. You are now ready to withdraw the axle from the front wheel, you will find it easier to remove if you place a screwdriver through the holes in the end of the axle and use it as a handle.

The front wheel will pretty much fall out once the axle comes out, just be careful not to loose the spacers or which side each one was on. Once the wheel is out, undo the mounting bolts for the front fender and remove it, it may require a little muscling as they are quite a good fit.

Front wheel off:



Remove the top triple and clipons:

Next, undo the top triple clamp and clipons and remove them, you don't need to remove anything from the clipons as there should be enough play to allow you to remove them.



Remove the forks:

Now its time to remove the forks, this is not as daunting as it may seem! Simply undo the pinch bolts on the lower triple and the fork will slide out.



Removing the head nuts and stem:

If you look at the top of your head stem tube you will see two nuts, and between them is a washer with some tabs on it, you will need to bend the tabs off the top nut like this:



Once you have done that just use a c spanner or a hammer and screwdriver to spin the locknut off completely.

Now you are ready to undo and remove the head stem tube and lower triple from the bike, undo the second nut while holding the stem tube and triple in place, once the nut is completely off you can slide the stem tube out of the stem.

Remove and set aside the top dust seal, you will need this when you put it all back together. remove the top bearing race and bearings. These can go in the bin.

If you look down the stem you will see the bottom race and an indent that has been provided to make life easier, just use something like a screwdriver or a piece of round bar to knock out the top and bottom races. Don't hit it to hard, lots of small hits are better than one big one because you are hitting the side of the race it will try and twist in its housing possibly causing damage. Here is where to hit it:



Removing the bottom race from the stem tube:

This will require a little patience and care, what you need to do is hit a cold chisel down between the dust seal and race, being careful not to damage the stem tube. It will take a while but it will come off. After the race is off, remove and discard the dust seal as well.



If you do damage the stem tube with the cold chisel, don't worry it's not the end of the world, just take a smooth file and de-bur it.

Time to put the new races in:

Well, your now ready to start putting it all back together, first thing is to grease the new bearings up, here is a video of how to do it properly (just a random bloke on youtube who is doing it right)



Next thing is to put the new dust seal (with the lip facing away from the triple and race onto the stem tube, there are a few ways to seat the new race but the two best ones are to use a piece of pipe to go over the stem tube and sit on the race and either a press or hammer to seat it all the way down.



There are also two ways to put the races back into the stem, either knock them in with a hammer or you can use a piece of threaded rod and a couple of large washers and simply tighten them down, using the old races as dies to press the new ones in.

Putting the stem tube and triple back:

Nice and easy... just slide her back in... one it is in there place your greased top bearing over the stem tube and then the old dust seal that you have cleaned back on with the lip facing down. After that put the stem nut back on.

Seating and adjusting the bearings:

Tighten the nut up till it is quite tight, but no need to pretend your superman :), then move the steering left and right a few times to seat the bearings.
Loosen the nut back off whilst holding the stem tube in place, and do it back up as tight as you can by hand, then give it an extra 1/4 to 1/2 a turn. This should get the right amount of torque and preload on the bearings.

Alternatively, if you have the special tool for the nut you can do it up to 22 ft-lb, seat the bearings and then do it up to 35 ft-lb.

Put your locking washer and locking nut back on and do the locking nut up hand tight, then holding the bottom nut in place with a c spanner continue to do the lock nut up until it lines up with the tabs on the locking washer. Now bend your tabs up...

Remounting the forks:

Place your upper triple back over the stem tube and put the nut back on to hold it on there but leave it loose enough that the triple can rotate.

Slide the fork through the lower triple, then through the clipon and into the top tripple then do up the bolt on the top triple hard enough to hold the for in place.

When you look at the fork you will see a ring around the top, this is to show where it should be aligned on the top triple clamp, the ring should sit about 1mm above it. Get it in the right spot and do it up to 17 ft-lb. Repeat for the other side.

Do up the nuts / bolts in this order:

1. The nut on the stem tube to clamp the top triple down properly. (76 ft-lb)
2. The pinch bolts on the lower triple (20 ft-lb)
3. The clipon pinch bolts (17 ft-lb)

Replacing the wheel:

Put the fender back in first, then hold the wheel in place (making sure you have it round the right way, there are direction markings on the rim and tyre) and slide the axle bolt through the wheel from the left side to the right. Put the bolt back into the right hand end of the axle and do it up to 43 ft-lb.
Now do up the right hand pinch bolts to 16 ft-lb.

Bolt your callipers back on, mounting bolts are to 22 ft-lb, and put the bike back on the ground. Bounce the front end up and down a few times (while holding the front brake in) to seat the axle properly then do up the left hand axle pinch bolts to 16 ft-lb.

Congrats, your finished!
 
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#5 ·
No worries guys... pics should be back up within 2 hours, bloody ISP keeps changing my IP address.... :cursin:
 
#6 · (Edited)
Thanks for this write up Nico!
Im going to do my bearing while I have my front end off during my 03/04 - 05/06 conversion.
Thanks a million. This will save me lots of time and keep me from speaking gibberish full of F words haha
Pressing the new race will probably slow me down a bit though...
 
#7 ·
I thought I might add some more to this thread...

C spanner

Undoubtedly some of you won't have a C spanner handy... I didn't have the right one either, so I made one...

It's nice and easy to make, all that you need to do is download the ZIP and print off the template, then cut it out and glue it to a piece of 3mm thick steel.

You then just cut out around the template and shape it until your happy with the result.

Here is a pic of the template:



And here is a pic of the completed spanner:



And if you ever need a different sized one you can just scale the template up or down to suit...
 

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#8 ·
nice write up!

another way to take off the lower bearing is to use an air hammer. i just did this same job on my KX250. if you dont have an air hammer, bring your favorite mechanic a coffee and ask him to give it a hit, only takes about 3 seconds.
 
#10 ·
Handy tool to have, but I just worry about taking it to far and damaging the stem....
 
#16 ·
Hey guys, so how tight do you put it? I have the propper tool to torque the nut down and it feels too tight at 35 foot pounds. Turned it lock to lock a bunch of times but it's not getting smooth as butter like it was before. It does have some crappy lithium grease in there right now, I just ordered Amsoil synthetic racing grease to put in.
 
#17 ·
I have mine down fairly tight, once the bearings have seated it doesn't need much extra to hold it all in place.

Are you using tapered roller bearings or ball bearings?
 
#18 ·
Tappered bearings by all balls. They turn smooth, but it just seems harder than it should.
 
#19 ·
Give them a few miles and see how you go mate, it will take a while for the races and rollers to seat and bed properly.
 
#22 ·
Great guide nico, thanks.

im about to do my head bearings but ive not taken the front end apart yet.

I was wondering if there is anyone whos already started the job and could take the measurements on the outside diameter of the outer races that fit into the stem?

ill use these dimensions to make a couple of plates which i can use wiht a threaded rod and some washers to re seat the new races.

if anyones got their bike striped down and able to measure the OD of the upper and lower outer races that would be great.

thanks
 
#24 ·
You have two races, and a ball between them:



When you turn the bars there is a little friction in there that causes that ball to roll, it will in fact travel exactly half the distance the top race does:



When you turn the bars back again, that ball returns to exactly the same position it had before you started, this is one part of the cause.

The other is the fact that there is an axial load that is always applied, and that load cycles as you travel down the road. All of the force that goes through the suspension also goes through these bearings and given that your bike spends most of its time (while its in use) with the bars in the central position almost all of the force is going to be concentrated on the very small contact patch that bearing is making with the races and eventually it will dent the race and cause the ball to go out of round. The combination of these two defects cause the notch you feel.

Tapered bearings overcome this to a point by increasing the surface area that the force is transmitted through by many times thereby decreasing the pressure at any point by a proportional amount.

Interestingly enough though, the increase in surface area has absolutely zero effect on the friction involved in the system so even though the contact area has increased there is no difference in the force required to turn the bars (when comparing new tapered rollers to new ball bearings - obviously replacing worn bearings with either variety of new ones will be an improvement).
 
#26 ·
You can't torque it down with a c spanner to a particular torque (not easily at least, there is a way to do it but it requires a bit of maths and making an accurate square hole) but you can seat the bearings and then put a certain amount of tension on them by rotating the stem (castle) nut about 1/4 - 1/2 a turn. This equates to a certain amount of downward pressure determined by the thread pitch and although approximate it's perfectly acceptable.
 
#27 · (Edited)
Just did the entire replacement job. Had to take steel pipe 1 1/2" and sand the end down to taper it so that it wouldn't touch the outer ring (the bearing assembly). That's definitely something to keep an eye out when installing the All Balls tapered cylinder bearing.

So with the pipe only touching the bottom race/inner ring, I slowly hammered it down rotating where I hit to evenly push it down.

I then used the old upper bearing, lower race as dies as you described to slowly hammer it down. Then the rest of the process was easy.

Hardest part was definitely getting the lower race off, The aluminum lower triple tree was marred from the chiseling and the flat bottom circular plain was also made uneven, I had to dremel/sand it down to make it flat.


Haven't ridden it yet , but it should be night and day. I bought the bike with a worn bearing with a VERY obvious notch right in the middle and I've been riding it like that for about 3000+ miles.




By the way, what kind of grease did you use?
I used the Silkolene Pro RG2 Racing Grease


Thanks again Nico for all your help!
 
#28 ·
Just about any bearing grease will do, I personally use a castor oil based high temp wheel bearing lube in most things I do so that there is no chance of damage to any rubber components like seals and boots.
 
#29 · (Edited)
I'm finally able to post up after so long.

I just did my bearings last month with the help of Nico's guide so I have to give a huge thanks to him. It was a lot more straightforward than even Honda's own service manual and saved me over $200 in the process.

The problems I faced were similiar to other members when dealing with the bottom race. Mine was seized and had to be taken to the local shop to be removed. I should have also had them put on the new race because it took me over 2 hours to tap in with a hammer and screwdriver. Frustrating.

Besides that small problem, it was a suprisingly easy job. If you've ever replaced a head-set on a bicycle this is really no different. Bicycle shops also sell the proper size C-spanner. I bought mine (Park Tools) for $20.

Thx again Nico!

-Oh yeah, where are the smilies (emoticons) in this place?
 
#30 ·
Thanks mate, glad to see you found this usefull!

And I have no idea where the emoticons are? :ponder:
 
#31 ·
J/k mate, to get to them hit "go advanced" in the quick reply box or click
which you will find just above the quick reply box on the left hand side of the page.
 
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