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[4]

How To Repair The Steering Head On My Motorcycle?

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malmac

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#1
27978217716_2f4532b3d4_z.jpg

I am looking for a quality repair - the problem is that the bearing seat is either worn or stretched, or maybe the bearings being made are a little under size - BUT the end result is that the bearing race is not a press fit into the frame. Does anyone have a quality repair strategy for such a situation.

Is it possible to shrink the bearing mount? If so how?

Yes I know there is locktite products - but I feel this is a last resort, not a first resort.

Any good ideas?????

Mal

PS the bike is a 1962 BMW R69s - for those who are interested.
 

malmac

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#2
27978217716_2f4532b3d4_z.jpg

Not sure why the photo did not come up in the first post.
 

Groundhog

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#3
I know you consider a bearing retaining compound a "last resort", but by my way of thinking it would be a first option.? Or are you trying to keep the bike absolutely 100% original?

I've used bearing retainer in a lot of applications and have always been satisfied. Steering head bearing have no load, heat or rpm. Very easy repair for a retaining compound.
http://na.henkel-adhesives.com/industrial/vehicle-repair-maintenance-retaining-compounds-22183.htm
Use the proper one and apply it correctly. That is what it is made for (do NOT use a thread locker).

Good luck on your restoration of a classic bike!
 

malmac

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#4
I will measure up the inside diameter and calculate the gap. While steering head bearing are not exposed to heat or rotation, they are subject to significant side loading - which is I guess why the metal has stretched over the last 50 years of use. I was thinking of some sort of shim - I have seen shims to repair the oil seal running surface - I thought maybe a sort of shim or perhaps an oversize outer race which I could turn down to become a press fit - yes I know, I am probably dreaming. I will investigate the chemical solutions.


Thanks
Mal
 

FOMOGO

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#5
When I run into situations like that I run around the i.d. with a center punch, top, bottom, and center about a 1/4" apart. This will usally tighten things up nicely. Mike
 

LucknowKen

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#6
Not necessarily a good idea but you could carefully wrap the race with a layer (or two) of HVAC metal heat duct tape.

premium-high-tack-tape.jpg
 

Fabrickator

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#7
This is what we did in the Harley dealership I worked at in the 80's (I was Factory Trained in Milwaukee). Evenly spaced centerpunch pricks and Locktite bearing retainer or equivalent. Let it set up over night. If the steering head bearings are adjusted properly and the forks work properly (no stretched springer stuff) it should hold forever.
When I run into situations like that I run around the i.d. with a center punch, top, bottom, and center about a 1/4" apart. This will usally tighten things up nicely. Mike
 

Tony Wells

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#8
Bore a tool with a few thousandths taper that will fit over the top of the boss. Pull it over with all-thread and a plate/nut arrangement on the bottom if you can't manage to get the frame situated in a press. Make sure the tool has a solid bottom so you can use a bar and hammer to knock it back off. Worst case, you could hammer it over the existing boss, even if you had to heat it, but cold work would be preferred.

Measure the wall thickness of the boss now and double it, add the desired ID size and you will have a finish size for the ID of the tool at the small end of the taper, which should end up with a short, straight section. It does appear that the OD of the boss is machined, and this remedy is based on that being the case. I have "shrunk" many thin walled parts with this method. It's simply a swaging operation. No centerpunch needed, but I will grant that the centerpunch is about the easiest way next to bearing retaining chemicals.
 

malmac

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#10
Thanks guys, now some ideas are in the melting pot, I can make a call on which option I prefer. Lucklily the frame is completely stripped - I do have a shop press and also I have a centre punch or two - I have some Loctite 680 but reading up the spec, maybe the Loctite 660 might be the preferred option. mmmmmm - he thinks.

Thanks guys


Mal
 

TOOLMASTER

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#11
Having broke several on my bmx bikes yeeeeears ago headsets always worried me on motorcycles..it is one thing to fail at 20 mph but 120 is a different story
 

malmac

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#12
I don't think the old girl ever got to 120mph but I take your point.
 

Tony Wells

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#13
One other thing to keep in mind is the original cause of failure. Although it may have taken many years to get to the current state, once you start moving metal, structurally it can be changed in a detrimental way. I would stronly consider turning up a reinforcing ring to fit around the OD, as thick as practical, depending on what type of cover fits over the bearing housing end of the head tube.

Another possible "repair", although not near the top of the list, would be to make such a ring and put a few set screws around it so they would bear on the OD of the bearing boss and put a little squeeze on things. I don't suppose you have a good way to bore that boss, do you? It could be built up in a variety of ways and bored to desired size. Or if you have TIG, you could machine it off completely and make a new insert.

Too many ways to skin this cat!
 

malmac

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#15
Tony, I like the way you are thinking - sort of looking for an over engineered solution rather than a adequate and workable fix (I appreciate other might express it differently)
I do have a milling machine and it has a horizontal and vertical drive. Just giving it a quick estimation - off the top of my head - maybe the horizontal drive coupled with my boring head could machine the bearing mount.

I also have a TIG welder - while I do not feel expert enough to just go for broke - I would certainly consider welding up the mount surface and then machining back to a suitable press fit. Tony I also like your idea of a reinforcing ring - with interference fit pressed over the outside of the steering head - I have an engineer friend who might run the numbers on which material, by what dimensions to achieve a suitable (what might that be?) increase in strength. I like the idea particularly for the lower bearing - which is the really loose bearing race (so the most stretched) - The top race would seem to get substantially less impact and strain than the lower race. I guess 50 years is fifty years - I know I have stretched in certain parts of my anatomy in that time.

Thanks heaps guys.

Mal
 

talvare

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#16
I would stronly consider turning up a reinforcing ring to fit around the OD, as thick as practical, depending on what type of cover fits over the bearing housing end of the head tube.
Personally, this is the approach I would take. I don't know how loosely your bearing race fits, but if you make the ring with a substantial press fit, you may gain enough shrinkage to make that race a press fit again.

Ted
 

malmac

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#17
27454007633_79eec16ed7_z.jpg

Here is my scale drawing of the steering head. I am not very bright so I like pictures.

I have measured the top mount - North-South measurement 50.95 and East-West 50.97 (so a little out of round.

Bottom mount North-South measurement 50.99 and East West measurement is 50.95

Bearing OD of taper Bearing race 50.93mm.

By test fitting the outer race to the bearing mount it also apparent that the bearing mount has been splayed at the mouth - and the measurements I have taken are about mid way down - so right at the base of the bearing mount they are probably very close to right if not right - however the splayed mount seems to be the issue I want to address.

So the idea to press a collar onto the outside of the steering head - would seem to have merit - the question is how much spring is likely to exist?
I squeeze it in, it springs back to basically where it has been stretched to.

Secondly what is the impact of heat? Then it is a case of how much heat?

Thanks guys for listening and providing a lot of much appreciated advice.


Mal
 

ryan79

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#18
sand the edges, put the middle ring/race in the freezer. heat the out edges, gease it then push and tap it in. done quite a few if them all balls conversions myself. plus make shure top and bottoms are correct. some times I,ve had to do a little more sanding on the inside than I, would like. just a sore thumb. but that's how mine have looked also. seems not rite but persuation will work.
 

David VanNorman

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#19
Could you heat shrink the part? Then make a ring to fit the outside.
 

malmac

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#20
Ryan, my problem is the bearing is loose in the race, I need the bore where the bearing fits to be smaller. David could you elaborate on heat shrinking the part (I assume you mean the steering head) - what temp would you heat the steering head too? Also given it has taken 50 years for the steering head to yawn - will it be more prone to stretching or will it take another 50 years to reoffend? If you see my grey hair (what I have left) you might appreciate I don't need to fix it for eternity - I just like the idea when the next person works on this machine will see the work I have done as elegant and competent (and while I hope that will be a long time down the track - I hope it remains worth maintaining).

Cheers


Mal
 

bpudney

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#21
As someone who has been riding/repairing/rebuilding motorcycles pretty much all my life, and has frequently encountered this "problem", here is my solution. Use a retaining grade of Loctite, up here it would be 609, or something like that. Clean the bores in the frame very, very carefully. Then clean them again. Get a long piece of threaded rod, studding, whatever they call steel rod with thread all over, in your neck of the woods, some suitable nuts, and some big washers that are bigger than the o/dia of the races. Length of the studding should be 50mm or so longer than the length of the headstock. Then clean the steering head stem again, and clean the bearing outer races. Apply the Loctite EXACTLY i.a.w. instructions. Assemble the race outers in the headstock, and clamp in place with the studding, washers and nuts.
As long as you stick to the instructions this works every time. Personally the thought of centre popping to provide a press fit leaves me rather cool, especially for a classic like your BMW!
best of luck
cheers
Bill
 

Billh50

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#22
I am surprised the race cup was not made to be replaced. All the motorcycles I have worked on the race cup can be tapped out and replaced. Maybe I have been lucky that way. But I would just use a bearing retaining compound as I know they hold fantastic. I have used the retaining compounds in work and know how well they hold.
 

juiceclone

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#23
I am surprised the race cup was not made to be replaced. All the motorcycles I have worked on the race cup can be tapped out and replaced. Maybe I have been lucky that way. But I would just use a bearing retaining compound as I know they hold fantastic. I have used the retaining compounds in work and know how well they hold.
I believe he's saying it's the outer race cup that is a loose fit in the frame boss. I would be questioning how that boss got loose as the most important item...looking for micro cracks, etc. Perhaps the new? race he is using is not correctly sized?? If no cracks/fatigue on the frame, then locktite , JBweld or some such epoxy based formula would do the job. If it's a "good" fit, just not a press fit, locktite is the way to go. The limitations of those products is high temp related, and therefore of no concern here.
 

Billh50

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#24
From the photo it looks like it is the outer race that is loose in the neck cup. The neck cup that holds the outer race is replaceable. That was what I saw. Guess I missed something.
 

Joe in Oz

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#25
I believe the head stem is a forging (going by the looks of my own R26). So you should be able to put a bit of heat in it - but not enough to heat up the oval tubes which are some kind of chrome-moly. The cup boss is almost certainly tapered from multiple bearing replacements, rather than 'rolling' wear. I would heat up the very top edge only and only just dark red at most. Then using a heavy hammer but with little force tap all the way around the top edge - checking the reduction of taper as I'm going around. once the bore is close to cylindrical again, I'd put the bearing cup in (preferably an old one or an old ball race the same OD) and then tap on any loose spots until it fits as close a perfectly as you can get it. So you are kind of reforging the boss. The cool it down, clean thouroghly as described by others.
Lastly Loktite the cup in. Should last another 50 years.... :)
 

Doubleeboy

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#26
Can't help you with your problem, but a lot of folks thought the r69S was one of the best BMWs ever for racing, including the great Reg Pridmore who won the super bike championship. I have no doubt Reg's bike could easily do 120. https://www.pinterest.com/pin/363595369892877554/

cheers
michael
 

David VanNorman

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#27
Mal,
you heat the area where the bearing light red and spray with water . That will shrink that area . don't get it any hotter than you have to do the job. you should be able to pull the races in without too much trouble. make a ring to fit around the the head where the bearing sits . That should do it.
 

malmac

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#28
Thanks everyone for your input - while I have not actually undertaken the repair yet - delays have been caused by other priorities. I am back in the saddle. My first attempt will be to make a tool for the press as outlined by Tony and put it in the press and see if I can effectively reduce the inside diameter to a better fit. As far as a reinforcing ring goes - I think I will try this on my second frame where my ambition is to customise the bike as an R69GS - scrambler with knobby tyres and high exhaust etc - sort a modern version of the old ISDT BMW's from the 1960's.

Mal
 

Billh50

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#29
Juice,
The boss that the outer race goes into is replaceable on many necks. It may look like it is part of the neck but sometimes is replaceable. I have replace them on Honda's, Triumph's and Harley's. That is why I say to look closely as it can be hard to tell unless you look at the inside of the neck also. I have replaced those cups many times through the years. If they are not replaceable I would prick punch the neck to make the race tight and also use retaining compound.
 

Tony Wells

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#30
I personally, and it's just my opinion, that punching the ID is not the best way to permanently repair this thing. Whatever stretched that ID would soon push down the area around the punch marks. Compare the surface area between the small upsets and an entire ID of contact. If I was out on the road that would be one thing, but Mal is in a shop where he doesn't have to compromise. And yes, I am considering that the area between those punches could be filled with a chemical. Again, to me it's a compromise. But that just me. Mal is free to do as he pleases, just as we all are.:)

I do entirely agree though, that if they were replaceable, that would certainly be the easiest, safest repair. My thoughts have been limited to a non-replaceable part.
 
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