Steering Head Bearings

[jmics19067]

You will only want to purchase the inner ring and roller assembly, as you don't need the outer race. Leave it in there and just clean it up well with a scotch-brite pad.

I disagree on that ,bearings and races are like bread and butter can't do one without the other. J.P. please atleast check to make sure that the race isn't worn or damaged. A big probelm on bearings like your steering stem< they never rotate completely like in a wheel bearing> is that they can develop flat spots where the contact points are most common. especially if the bearing preload wasn't set correctly. Add in the stress/shock load of a few jumps and some monster whoops that you would most likely have the bars in the straight ahead position. I think Brinnelling would be the proper term.

 

[Jaybird]

Unless the stearing head was loose, or the inner part of the assembly damaged the race, I doubt very seriously that there will be alot of damage to the races. It will be obvious when you clean them up with a scotch-brite pad if there is in fact some damage like "Brinelling".
Now there may in fact be what is called, "Fretting"...which occurs on a race and bearing assembly when continuous vibration takes place. This would be the removal of very fine particals at the microscopic level. Fretting is sometimes called "false brinelling".
You will probably need to take the bike to a shop to r&r the races in the steering head. I would r&r the whole assembly for sure if it were an older bike.
JP, was the inner assembly broken apart or were the bearings just dry?

 

[JuliusPleaser]

The cages were intact, but there was very little grease in either bearing. I did a quick visual inspection of the outer races when i took it all apart and they look like they're in decent shape. I'll do a closer inspection before I put it all back together.

 

[Jaybird]

Be sure you clean them up real well as base soap and dirt tend to get ground into the surfaces. Dirty races look"stained".

 

[jmics19067]

I am missing something here, if the bearings are bad enough to be replaced the races should show the same wear/damage. That and knocking out the races of the steering head has always been easier for me than removing the bearing from the triple clamp stem.


Actaully I am quite surprised Jaybird , after reading your many well informed posts about chain and sprockets that you don't treat bearings and races as the same.

Now I am only going by what I was taught so many years ago where I work pertaining to wheel bearings of highway trucks almost exclusively. The rule of thumb is that if you have to think about it replace it. And as far as I can remember if you have a dirt scratch on the bearing you will have a corresponding groove in the race, if the bearing was flaking apart you will have little spots of bearing welded to the race and if you broke a bearing you will have a crater in the race.
Now the two situations are greatly different and the possible catastrophies of failure are of more dire circumstances on what I was taught. Thinking if you lose you steering stem you bite it and possibly take out someone else on the race track where if a 700lb<?> dual wheel assembly comes off a trailer at 50 miles an hour into oncoming traffic things can get a lot uglier a lot quicker.
Now you may be saying I am wasting my time and money when I am saying its cheap insurance while you are there. Quite possibley we both could be right in that respect. But I will never really enjoy the thought of using a new bearing on an old race.

 

[Battered Sav]

Gotta agree with jmics, it just doesn't make sense, the outer race would be fairly cheap, if available separately, and for just a few taps with a drift, you get peace of mind.
If the bearing was damaged to the point of seizure, i couldn't see the race being very healthy.
Besides all that, whenever i've bought head bearings, OEM or alternative supplier, I'm nearly positive that they came as a set, and couldn't be purchased as individual pieces.
When recently replacing the nephew's h/b on his 92 KX80, the bike shop had no idea about the dust seal on top, bearing shop said "yep, this is the number and I can have one for you tomorrow"
I'll have to admit that I've only done this job a handful of times, managed to drift out the races each time, but the headstem inner race was always a shop job.
Sorry to disagree Jaybird, I usually enjoy and learn from your posts, It's just that this doesn't seem right. :confused:

 

[Jaybird]

He said the bearings didn't have much grease in them. It's very comman for them to look dry after they have been in awhile. I see no reason to get the outer race unless they are needed, and YES they are sold seperately in most every instance. Go to a bearing website and see what you find. You will need to look at the page concerning ISO 355 tapered bearings.

After rereading this post, JP were the bearings actually trashed or just that they looked dry? Why did you use the term "seized"? If they were simply low on grease, I would clean the original ones, grease em up and go.

jmics, surely you will agree that a wheel bearing is quite a different story than a stearing head bearing that doesnt even make a full rev.?
I will treat any mechanical item with what is warrented, and I just don't see the races being replaced in this instance, probably not the bearings either...JP did state that there was very little grease in them...so I'm confused as to why he stated they were seized in the first place.
I have installed and maintained a few bearings in my day...probably hundreds and hundreds of them...from itty bitty ones to ones that take overhead cranes to handle. But hey, I may be wrong here.

 

[JuliusPleaser]

After the bike sat for a few weeks, I had to force the bars to turn. When i grabbed the bike to load it into the truck, the bars wouldn't turn at all. Seized may be the wrong term, but the steering stem was definitely stuck in the straigh ahead position.

The rollers looked like they were damaged, but the outer race looked ok. I'll tackle the project tomorrow and post the results.

 

[jmics19067]

jmics, surely you will agree that a wheel bearing is quite a different story than a stearing head bearing that doesnt even make a full rev.?

although I wont know all that is different between the two I obviously can see how they are different. Heat is a very major concern in the application I was taught for. And I was only taught by older mechanics working on wheel bearings. Habits good or bad are hard to break though and I will continue to treat bearings and races as one. Hey my money my feel good factor right? ;)

Any way I was definately trying to give some insight on what I was taught and what I saw or at least what I believe I saw in what I have the most experience doing. On trailer bearings I have most likely seen every type of failure even though I wouldn't know all the different problems or the actual causes. Headset bearings I can only account for two problems that I can immediately specify rust damage from lack of decent grease and broken/worn from being loose where the cases I saw included having to change the races. I have seen a few strange problems in needle bearings in Ujoints in badly set up angles of drivelines. The local reps of Spicer and International Harvestor are the ones that gave me the term brinelling when I had a problem with a new truck eating Ujoints a few years back.

When I saw the actual title of this thread I was amused by its sub title and yet was alarmed since I have seen bearings with flat spots on the previously stated truck Ujoints. It's problem being a bad angle<actaully none> so the bearings wouldn't roll and spread the grease around. I have also seen wheel bearings flat spot because they where siezed but I am pretty sure no one would try and ride headset bearing like these since they where tighter than the gates of Hades.

I have damaged the cages before on bearings from mishandling ie. dropping them on the floor or not getting a good grip with the pry bar while popping out the seals. In those cases I have only changed the bearing and not the race and I can't say whether or not they prematurely failed . Never heard any complaints anyway.

Jaybird, I definitely trust your knowledge and insight but this one issue had me raise my eyebrow :think:
I know lets blame J.P. :) Julius, please give us all you know about your bearings . Did you actually see damage on your bearing? If so what did the damage look like and is it on the race? And more importantly did you get that thing back together yet so you can ride :thumb:

 

[Jaybird]

LOL...I don't want to blame anyone for anything. :)

OK, from the sound of it, there may well be a flat spot on the race. For the stearing to not want to turn at all, something is seriously wrong.
In this instance, yes...I would probably change the whole schmear out.
I would give a good look at the stem as well.
Make certain you don;t get things too tight, JP. I like pull the bars just a little to one side and tighten the nut until it just does offer some resistance without falling all the way on it's own. It is possible to get the nut too tight and damage things. Too loose and you can see some headshake.
Good luck!

 

[JuliusPleaser]

After seeing Ping's triple clamps explode last year, I'll be paying CLOSE attention to what I'm doing.

I cleaned the bearings really well with brake clean, and they will barely roll. The rollers look like crap, while the outer races (and the lower inner race) look pretty good.

Blame it all on me. I can handle that. As a matter of fact, I kinda miss taking the blame for everything. :confused:

 

[jmics19067]

After the bike sat for a few weeks, I had to force the bars to turn. When i grabbed the bike to load it into the truck, the bars wouldn't turn at all. Seized may be the wrong term, but the steering stem was definitely stuck in the straigh ahead

sorry I didnt see you post in the middle of my reply with all my retyping of my grammar errors. I can easily see the grease caking up being a problem but that wouldnt mean having to change the bearing ,just harder to clean well.

when you give us a detailed report on your bearings do you run the preload on your stem bearings tighter than normal to help fight headshake? How tight do you have things when you assemble it all together with the fresh grease? I can see it just might be possible that you are crushing the bearing and then the lack of decent lube and fixing it before the damage transferred to the race. Although the time frame you have to work with I would believe is really small.

 

[JuliusPleaser]

I've never had the steering head apart on this bike. The problem didn't stem from too much grease. There was no grease in the bearings at all. I'm assuming that water from repeated bike washes compromised the integrity of the rollers.

I have never tightened the steering head at all. I noticed that the steering felt a little stifffer the last time i rode it, but I never tried to change the tension on the bearings.

 

[RM_guy]

You guys are going to love this. I’ve actually run crappy pitted steer stem bearings and run them tight to act like a steering dampener of sorts. My bike was a bit twitchy at speed and the extra drag that the pitted bearings gave helped keep the front end more stable.

I still kept them clean and well greased, just worn and pitted.

 

[jmics19067]

what I meant by the grease "caking" is that grease breaks down. It no longer has that jello pudding consistency but more of a waxy crumbley feeling to it .

dang just one of them things I wished I could of seen.


RM_guy,

man that would keep me up at night.

 

[RM_guy]

Originally posted by jmics19067
[B... RM_guy,

man that would keep me up at night. [/B]

I told you you would love it ;)

 

[JuliusPleaser]

Update: I just finished installing the new bearings and fork seals. Everything went together easily, and the new OEM bearings are sealed. Chad at Alabama Motorsports says the bearing failures are a common prob on YZ250Fs. I went ahead and replaced the races while I was in there. I'm gonna do the brakes, sprockets, and chain tomorrow, and then it's time for a test-ride. (IF the rain will stop for 5 freakin' minutes. . .) :think:

 

[jmics19067]

glad all went relatively smooth for you. Why does the head set bearings fail? Is it because of the hot motor oil in the frame making the grease thin and run out? something to think about while doing your normal maintenance and maybe including adding fresh grease at a more accelerated time frame.

 

[JuliusPleaser]

I never saw any evidence of grease leakage around the frame head, so I'm going to say the bearings never had any grease in them in the first place. The original top bearing was devoid of any kind of seal. It would have been too easy for water to fill the frame head while I was spraying it with a hose.