Author Topic: Tapered Steering Bearings Thread (Read 207745 times)

ekim98 · « **Reply #150 on:** November 24, 2007, 02:08:43 PM »

Good pictorial on tapered bearing swap. Your could have gone to 250 degrees on the bearing and not hurt anything, but if you do heat it up in oil, gives a much more even heat. Little harder to handle but you shouldn't have to do any pounding if you plan right.

kirkn · « **Reply #151 on:** November 24, 2007, 02:19:49 PM »

Thanks for the comments.

The lathe / mill option is something I was trying to avoid, i.e, the use of specialty tools, skills or knowledge. Kind of like the difference between doing it yourself and just taking the whole bike down to the shop...

As for the heating in oil, I've heard about it, and I thought about doing that, but, as you say, it gets pretty messy. So, I just left it in the oven for an hour with the oven set at 195. I figured that was enough time to evenly heat the whole thing.

I wished I HAD gone to 250, because I'm really curious now to see exactly what difference that would have made.

Along those lines, at work, I've used liquid nitrogen to cool parts that require a large press fit. But again, that's a lot of specialty tools and equipment.

Kirk

jsaab2748 · « **Reply #152 on:** November 24, 2007, 02:23:33 PM »

It is possible to space the upper fork cover seals from underneath with
washers or big rubber o rings. Moves the upper cover seals upward, closing up that gap and barely noticeable unless you're really lookin for it. Worked on my 550 real good.

HondaMan · « **Reply #153 on:** November 24, 2007, 04:04:19 PM »

Kirk;
Most EXCELLENT tutorial work!
I'm curious about the ending (at this point), because I have not seen it come out this way in the past.
This might seem like an odd question, but...can you post a picture of the packaging that the bearing kit came in? I'm interested in the verbage and branding, in particular, if legible.

Last Fall, before the rush started for the HM ignitions, I was building some 10 bearing "kits" for these bikes. I have them almost finished: they require machining of the stock bearings now, to make them fit (back in the 1970s you could buy off-the-shelf Timkens and Bowers to fit, but those sizes aren't made anymore). I hope to avoid whatever caused this issue, and maybe if I can compare the (above) pictures to my notes I've been compiling, I might find the "why did this occur?" answer.

Somewhere in the back of my (foggy) memory, there was an issue about the lower spacer. What I can't remember at this moment is: was it that I had to make thinner spacers than everyone else, to make these fit perfectly? I remember selling these spacers to people at one time, years ago, and sold the last one to someone here at SOHC4 (don't remember who, now). I have to make some to go with these kits.

kirkn · « **Reply #154 on:** November 24, 2007, 05:59:04 PM »

I'll get you the pictures and post 'em. What I got was whatever came from being ordered over the phone from the Dennis Kirk 2007 street bike catalog. There were almost no directions whatsoever. One sheet of about 3 sentences mentioning the need to check stack height of the lower set, and select the appropriate spacer.

The issue seems to be the UPPER bearing set. With the correct spacer selected for the lower bearing, the lower triple clamp is positioned exactly as it was with the stock ball bearing setup. Therefore, if the headlight ears / fork covers don't fit between the upper and lower clamp, it must be because the upper clamp was moved upwards. And, indeed, the new upper bearing set was taller than the stock setup.

I did notice standard bearing number markings on the new pieces, but didn't think to write 'em down. Maybe if I go back thru the pictures, I might be able to see something.

754 · « **Reply #155 on:** November 24, 2007, 06:05:26 PM »

I thought I had read somewhere that they take a standard bearing and grind the OD to fit.

If that is the case and you order that number you will have a race that you will never get in.

kirkn · « **Reply #156 on:** November 24, 2007, 06:21:05 PM »

Here y'go:

The printing on the edge of the plastic box, the label from the box and the instructions, in their entirety from the box. I didn't notice until just now that the part number on the side doesn't match the part number on the face. Hmmm.... maybe I'll go back to the DK catalog and refresh my memory as to what I ordered. It never occurred to me to check when the carton came in the mail.

Oops, no wait a minute, I see now that the DK label refers to a Vendor PN, which is the All Balls part number. OK, should be good to go.

kirkn · « **Reply #157 on:** November 24, 2007, 06:30:36 PM »

OK, here's a crop and extreme closeup of the only picture I took of the kit parts. This is the upper bearing.

You can make out the manufacturer KML and the part number, as near as I can make out L26-?05H

Best I could do.

pddpimp · « **Reply #158 on:** November 24, 2007, 07:35:45 PM »

Great write up

I did this same project last winter and boy does it help stablize the steering. I had the same problem with the headlight ears. I went down to the local hardware store and bought some large drain pipe washers (black) and it worked like a charm.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #159 on:** November 24, 2007, 11:02:20 PM »

This would be much easier for me to guess if I were sitting there with you. I first noticed the top race is taller by approximately the width of the washer you added to the bottom. This made me think that perhaps the top race additional height makes up for the width of the washer? Then after you added the pictures of the packaging I noticed the following:

"One of the washers MAY be required. WHETHER and which may be required."

Key words MAY and WHETHER jumped out at me. I read that a washer may NOT be required from both words. Is it possible that neither washer is required due to the extra height of the top race? Is this particular kit made for bikes other than the 750 also that would need one of these washers when our bikes don't? Without the extra height of the washer would your fork ears fit more snuggly like they are supposed to? I just checked mine out. The bottom dust seal is protruding somewhat downward from inside the steering head and there is NO spacing washer underneath it. I do not have fork ears on my F so I'm uncertain of that part of this equation. It's been quite a while since I replaced mine and I definitely do not remember what I did.

Now, second thought. Are the top and bottom bearings/races identical in height? The reason I ask is that once you installed both of them, one sticks out (the top) and the other (bottom) is up inside. If the 2 are different heights perhaps they could be switched around.

Anyway, those are my theories. I do really like your posting. Once you get this figured out I think you should go back and make any necessary alterations then we can have this added to the FAQ, Tricks and Tips, or Restoration sections. Keep up the good work.

Jerry

Nothing like arm chair mechanics.

kirkn · « **Reply #160 on:** November 25, 2007, 06:06:35 AM »

Well, good question. It DOES appear that the amount of the gap is the amount of the thickness of the new spacer.

But, the new washer is supposed to position the lower triple clamp. And, according to the way it went back together, it put the lower clamp exactly back where it was.

Now, if I did without the spacer, yes, that would make up for the gap due to the new upper bearing set being taller. BUT, it would allow the lower clamp to move upward and, without some grinding on the lower clamp around where it fits into the frame neck and some grinding around the steering stop lugs, the lower clamp would interfere on the frame neck.

So, as it seems, one would either have to grind material away on the lower clamp, or one has to do something to close up the gap on the headlight ears. Neither is impossible, but its disappointing to have to do something like that with a "bolt-on" kit...

The upper and lower seats are NOT interchangeable. The lower one is larger in diameter. The lower is too big to fit in the upper, and the upper is too small to fit in the lower.

Something'll work out...

Kirk

Jay B · « **Reply #161 on:** November 25, 2007, 06:07:59 AM »

Hondaman, I have a new All Balls kit in my hand, same PN as kirkn's. The lower bearing is marked KML 30-50H. The lower outer race is marked the same. The upper bearing and outer race is marked KML 26-485H. Problem is though, the 4 isn't really a 4, but rather sort of a plus sign with a curved eyebrow over it. At first I thought maybe it was a capital G, but the number 4 is the closest thing I can come up with. Both the inner and outer races look the same, so it isn't a misprint on the bearing. You can kinda see it in the last pic. HTH

joeb · « **Reply #162 on:** November 25, 2007, 06:18:17 AM »

Very good this info will come in handy for people in the future I also did the freezer trick,but unlike you I ended up using the thicker spacer on my 78 super sport, I also noticed you did not use the seal on the bottom race or did I miss something. Just curious but a real nice wright up on install.

kirkn · « **Reply #163 on:** November 25, 2007, 12:27:05 PM »

SUCCESS!!

OK, the underside of the adjuster nut / dust shield has this raised circle inside. On the stock setup, the upper bearing race fits inside this circle. On the new installation, the new dust seal sits ON this circle. This accounts for the extra few mm. The new upper bearing, WITHOUT the dust seal, fits inside the circle just as the original did.

So, I reassembled the upper bearing leaving the upper dust seal out, since it really doesn't seal against anything at all. With the tightness on the bearings set, and the upper triple clamp reinstalled, the gap at the headlight ears has disappeared and they fit just as snug as at the beginning. The adjuster nut / dust shield looks good, too. I think I'll be good. No home-made spacers or shims required!

So, as far as I'm concerned, this is complete. And, this makes this a bolt-in installation (other than the heating/freezing/pressing issues). The kit just includes a few extra parts (a thick spacer and a dust seal).

Joeb, I DID install the lower dust seal. Look again at the picture showing the completed pressing. It's there.

kirkn · « **Reply #164 on:** November 25, 2007, 12:31:14 PM »

And, while I had it back apart, I tried to get a closeup of the upper bearing markings. So, Hondaman, now you know.

Good Luck to you all on YOUR projects.

Kirk

UnCrash · « **Reply #165 on:** November 26, 2007, 08:06:15 PM »

Excellent write up.

I'm thinking of doing this job on my upcoming project.

Your documentation is invaluable.

Many thanks,

Ben

HondaMan · « **Reply #166 on:** November 26, 2007, 08:26:06 PM »

Great work, all of you guys!

I know for sure the bearings are modified, as no one now makes the sizes we used to be able to get. The upper set requires the OD of the cup be ground off, and the lower set requires the ID of the bearing be bored. Neither is easy to do! I have the OD parts done, have to finish the ID, then I will have 9 sets of Timkens available (1st one is mine, ALL MINE, HA, HA, HA, Ha, HA....!). The KML bearing is better than the JIS ones I got from a local guy, though: those should actually match the bearing tapers. The JIS upper race cups are not the same taper (2 degrees different) as the bearing, requiring a lengthy settling-in process that has yielded a stiff-steering front end.

I miss my Timkens.

squirley · « **Reply #167 on:** January 16, 2008, 10:09:46 PM »

I realize that this topic has been covered a hundred times, but...
I was wondering if anyone knows the size of the bearings for a cb550, particularly the upper bearing. I am trying to locate a tapered bearing that is the same as the tapered bearing replacement for a 550, but have a 2mm larger inside diamtered stem hole. In another words, I need the same dimensions exept inside diamter needs to be approx 30mm for stem clearance. Thanks all
Jens

crazypj · « **Reply #168 on:** January 17, 2008, 12:53:22 AM »

They are not a stock bearing so you can't order them cheap anywhere, The kits are about as cheap as you get.
If you have access to a centerless grinder you can get them to fit steering shaft and grind the outside to fit frame.

PJ

squirley · « **Reply #169 on:** January 17, 2008, 07:47:09 AM »

You are right about them not being a stock bearing.

CRAZY: It is difficult to understand what you said in your reply. Were you saying that I should take off 2mm of material fron the inside of the bearing? What would I grind on the outside to fit the frame?

754 · « **Reply #170 on:** January 17, 2008, 08:19:46 AM »

The outer race. Like has been mentioned they are a standard bearing, then they are modifed.

squirley · « **Reply #171 on:** January 17, 2008, 08:47:19 AM »

Thanks 754, I did know that they take down the race, but the last post was confusing. I guess I should ask if it is possible to take 2mm of the inside diamter of the tapered bearing?

Second scenario, let's say I keep the top ball bearings, would it be possible to take 2mm of the inside diameter of the upper bearing seat and the upper bearing race race?

turboguzzi · « **Reply #172 on:** January 17, 2008, 10:14:37 AM »

here are the dimensions:
http://www.sudco.com/vol33/181.pdf

the cb550 are SSH750

went throught the same doubts when trying to fit different triple clamps to my racer which had 25mm diameter internal in both top & bottom bearing.

went through the whole SKF catalog and still couldnt find what is the original bearing that the SSH750 uses as a base. there are plenty of bearings with close dimensions, the main problem is that each has a differetn cone angle in the races. If anyone knows what is the standard bearing that they use, I'll be happy to hear.

looks like I'll have to turn a custom stem if I want to use these alternative triple clamps. this solution is pretty common.

TG

squirley · « **Reply #173 on:** January 17, 2008, 11:27:10 AM »

Well, heres my next quesiton.
The dimensions listed for a cb550 roller bearings are

26x48.5x15.2

So the inside diameter is 26mm, the outside race diamter is 48.5mm, and the 15.2 is...?
Is it the length of the sloped bearings?

Last question, would it be safe to lathe of approx. 2mm of the outside diamter of the bearing race? say a 50mm O.D. down to a 48.5mm O.D.?

Thanks for the link turboguzzi

crazypj · « **Reply #174 on:** January 17, 2008, 11:29:18 AM »

Quote from: squirley on January 17, 2008, 07:47:09 AM

You are right about them not being a stock bearing.

CRAZY: It is difficult to understand what you said in your reply. Were you saying that I should take off 2mm of material fron the inside of the bearing? What would I grind on the outside to fit the frame?

As said in the post below your quoted one, you grind outer race. If what I said is too difficult to follow/understand you probably don't have machining experience.
You cant turn bearings and get them accurate. They are ground to tolerance of about 1~2 microns.
Paying someone else to do machining is a lot more expensive than buying the kit.
I see no other reason for your question if it isn't to save money
BTW, the 15mm is stack height of bearing, about 3mm more than stock
PJ

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Author Topic: Tapered Steering Bearings Thread (Read 207745 times)

jsaab2748