1969 commando Roadster steering yoke bearings

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It's been a while since I messed with these because well, it was giving me a bit of a headache.

New roller bearings from reputed british parts shop. Installed them and bolted yoke together. The bearings sit proud of the neck. Should I just roll with it as is? or buy thinner bearings?

if just rolling with them sticking proud of the neck, what is a rubberized dust cover that will work? I have heard tell of a fabled 80's set that worked but can not find them. Tried making my own, but yeah, imagine 5th grade science project.

Will post more detailed measurements of bearings and neck etc tonight when home.

Thank you.
 
The more conventional up grade is a pair of ball bearing like all series 2+ commando (71+). You only need to buy the special series 1 spacer tube which is a bit longer than the later bikes.
The bearing pockets in the neck and triple trees are entirely different from post 68-69-70
 
EVERY other bike, worth a crap, uses taper roller bearings in the steering head. (EVEN post 1971 Triumph T120s and T140s do ... o_O)
I ALWAYS upgrade my British bikes, my early KZ1000s, and all my other bikes that had, ugh, ball bearings --- to taper roller bearings. No brainer IMO. Of the eight Nortons I've had since 1982, and all were 1971 or newer; I upgraded to taper rollers. They do make the top yoke a little bit higher, even making the fork lock irrelevant; but worth it to me. Norton used, ugh, ball bearings --- cause they were cheap and built to a price. Many things on these old bikes "kind of worked" ... but that is it. It is up to you to upgrade your bike to better parts, or be a purist and keep it as "original when built ... with all its many, many ... "compromises." Maybe some folks choose to use the crappy Portugese ball bearing for the layshaft too; because "that is the way it was built originally." Then have fun when the gearbox locks up --- and destroys itself. I know, bit of a rant, I just don't understand why some folks insist on the "OEM" ball bearings in the steering head --- WRONG application of that type of bearing --- but it is CHEAPER. Just my 2 cents ...
 
One issue I found when I fitted tapered roller bearings to a dry frame Triumph was the bottom bearing (being deeper) is then far more exposed to the elements. Triumph used a seal on the oil in frame models to get around this issue. I'm not sure whether the same problem exists when fitting them to a Commando.
 
EVERY other bike, worth a crap, uses taper roller bearings in the steering head. (EVEN post 1971 Triumph T120s and T140s do ... o_O)
I ALWAYS upgrade my British bikes, my early KZ1000s, and all my other bikes that had, ugh, ball bearings --- to taper roller bearings. No brainer IMO. Of the eight Nortons I've had since 1982, and all were 1971 or newer; I upgraded to taper rollers. They do make the top yoke a little bit higher, even making the fork lock irrelevant; but worth it to me. Norton used, ugh, ball bearings --- cause they were cheap and built to a price. Many things on these old bikes "kind of worked" ... but that is it. It is up to you to upgrade your bike to better parts, or be a purist and keep it as "original when built ... with all its many, many ... "compromises." Maybe some folks choose to use the crappy Portugese ball bearing for the layshaft too; because "that is the way it was built originally." Then have fun when the gearbox locks up --- and destroys itself. I know, bit of a rant, I just don't understand why some folks insist on the "OEM" ball bearings in the steering head --- WRONG application of that type of bearing --- but it is CHEAPER. Just my 2 cents ...
Never had a problem with the ball race bearings on my commando so I've never thought about changing them , what problem did you have? How do you adjust tapered roller bearings when fitted to a commando?
Modern sports bikes have gone back to cups and balls I believe
Anyone fitting an original Portuguese layshaft bearing must be nuts,I've never heard of anyone doing this?
 
One issue I found when I fitted tapered roller bearings to a dry frame Triumph was the bottom bearing (being deeper) is then far more exposed to the elements. Triumph used a seal on the oil in frame models to get around this issue. I'm not sure whether the same problem exists when fitting them to a Commando.
A mate of mine who is a very high mileage rider always breaks the rubber seal off the bottom bearing so that moisture or any water finding its way in can now get out
He says the steering bearings last much much longer without the seal but with decent grease
 
Never had a problem with the ball race bearings on my commando so I've never thought about changing them , what problem did you have? How do you adjust tapered roller bearings when fitted to a commando?
Modern sports bikes have gone back to cups and balls I believe
Anyone fitting an original Portuguese layshaft bearing must be nuts,I've never heard of anyone doing this?

New to Nortons, and this one was a basket case. There were no bearings, ordered a set that said they were for my year ride and what came was tapered bearings.
 
Ball bearings 6205 2RS are the wrong bearing for the application going by the book. But in this case the book is wrong, no idea why but they do work and I am sticking with them.
 
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There were no bearings, ordered a set that said they were for my year ride and what came was tapered bearings.

Could you confirm which "set" (2 sets?) you ordered as the correct bearings are two sets of cups and cones each with 18 loose balls?
 
Could you confirm which "set" (2 sets?) you ordered as the correct bearings are two sets of cups and cones each with 18 loose balls?


New Norton Commando tapered head bearing set. Replace your old and worn out stock steering head bearings with this quality made bearing set. For the unaware, tapered neck bearings are stronger and far superior over the original ball bearings. Replaces Norton part number 030205, 03-0205, 06-7604 and 067604.

Included are tapered bearings to cover your bottom and top neck. Fits most Norton Commando, Atlas, Dominator, and many other Norton twins. Please refer to your parts book to ensure the best fitment.


 
Out of interest
How do you adjust these tapered roller bearings on a commando?
Is it done with a shorter spacer and shims?
Cheers
 
Slim line and series 1 commando, bypassing the easier 6205 ball bearing upgrade, should have a slightly under length spacer tube, then shim the roller bearing to a slight preload. (whole seperate process and discussion) The adjuster nuts would then be properly tightened to above the expected ever load to prevent nut/stem damage from the pounding of the suspension.
Similar process for 71 and up commando but shorter installed length and spacer tube.

from classic british spares
" Please refer to your parts book to ensure the best fitment. "
IMO complete evasion of the real engineering details = You're on your own sucker!!!!
 
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Slim line and series 1 commando, bypassing the easier 6205 ball bearing upgrade, should have a slightly under length spacer tube, then shim the roller bearing to a slight preload. (whole seperate process and discussion) The adjuster nuts would then be properly tightened to above the expected ever load to prevent nut/stem damage from the pounding of the suspension.
Similar process for 71 and up commando but shorter installed length and spacer tube.

from classic british spares
" Please refer to your parts book to ensure the best fitment. "
IMO complete evasion of the real engineering details = You're on your own sucker!!!!

Hey, happens all the time. I bought what I thought would be a 'upgrade' only to have issues of fitment. Thought I would come here to get a straight answer, which it seems I should just toss these and get 'stock' bearings.
 
When I decided to renovate the front fork on my Commando I was surprised that the headstock was supported and rotated on two single row deep groove Conrad bearings. My Triumph has the traditional cup and cone arrangement with loose ball bearings while my BMW has two angular contact roller bearings, as does the Buell.

From design experience a single row Conrad bearing, while ideal for supporting static and dynamic radial loads has an axial capacity – rule of thumb – approximately 10% of it radial capacity. In this case the 52mm OD x 25mm ID and .15 wide bearings have a published static load rating of 7 kN.

Doing some quick math in my head and approximating fork geometry, 260 Kg of bike and rider evenly distributed between front and rear suspensions and using a 30degree tire patch to center of headstock angle (rake on Norton is about 28 degrees and trail is about 2.5”) results in 112 Kg of axial load. If axial bearing capability is 700N / bearing, combined axial capacity is 142 Kg. This is purely static and ignores dynamic loading from braking and road input and steering loads. Add a passenger and I’m already over.

As engineers we were taught to “look at the parts”, the original bearing as installed rotated freely, had no “notchiness” from race dimpling and other than looking 45 years old were good for another 25,000 miles. I bought replacement (Timken MIUSA) bearings.

For laughs I did a quick free-body of the loads into the headstock – primarily from braking and vehicle/rider mass and see that even the radial capacity of the bearings is over the static bearing rating.

So given the axial and radial calculated loading and the history of minimal issues over the 10 years and 55,000 units of Commandos built – what am I missing?
 

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what am I missing?
Well it sounds like you have a good idea for the 71-75 commando front end.
The OP has a series one (68-70) commando which has cup and cone set up like your triumph.
I don't have a big problem with the tapered roller bearings per say. I'd like to think that we'd agree that just slapping them into a featherbed with 26 tpi stem nuts, early commando with 28tpi stem nuts or late commando with 14tpi stem nuts requires better than " just crank that sucker down"... No data or procedure exists that Ive noticed in the last 30 years.
While I'm a radar and high voltage technician (retired MSGT usaf, I was in a fairly heavy mechanical environment driving radar antenna cabs weighing tons..I did a lot of mechanical work too.
In high stress taperd roller bearing applications I would fully expect a shimmed column to preload the bearings to withstand radial and axial loads without moving the stem nuts on the threaded shaft, once set up.. I have bought tap and die to clean up/salvage damaged items that may have been from sloppy or haphazard assembly. An example is the front wheel bearing on my Lotus Elan. Unlike my chevy which the front bearings were snug and then back off one slot on the castle nut. The lotus is shim adjusted then the axle nut is socked down real tight.
So these 3 norton front ends "can" all use the same taper roller bearings. I think a more sophisticated setup is better than "gooten tite" being the bearing prelod or being slack.
There is nothing in the "parts book" or service manual to set them up with taper roller bearings.
 
Although AN lists the cup and cone sets for '68 - '70 there have been a few reports of '69 models having what's been described as "angular thrust bearings" with "felts".

The parts changes for '69 'R', 'S' and Fastback list two "18263 ball race" and two "15631 Frame ball race felt washer" instead of the previous cup and cone sets but as no spacer tube is listed it seems doubtful 18263 was the 6205 deep groove bearing used later and was an angular thrust bearing (7205?).

AN list 03.0205 as:
"FORK HEAD BEARING F/BED/EARLY C, Rotary (55.0357)"
"EARLY C" presumably means early Commando but as far as I'm aware the 30203 taper roller wasn't originally fitted to any early Commando.
 
there have been a few reports
Love them "reports"

The 18623 as a 7205 with only 15MM wide sounds like a "cartridge" cup and cone. $19.95 ea from VBX
Not bad other than the hit or miss "gooten tite" preload method. 15623 as a felt or gasket paper to keep grit out helps...
I have not yet found 25mm ID shims for blue print adjustment of a preload.
I envision setting a dial indicator measured end slop, then remove shims for a net -.005" (example) preload.
 
Here are the original steering bearings from my March ‘69 750 S.
I did as a Dave mentioned, put later Commando ball bearings with modified tube spacer. I can always go back to the original if needed.
1969 commando Roadster steering yoke bearings
 
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