I have some upgraded steering head bearing sets available. These replace the cup and cone sets originally used, are sealed for life and do not require adjustment. No modifications are required to fit as the bearings have been reground for the BSA application.
Sealed ball bearings of this type were standard fitment on Norton Commandos.
They will fit A,B and all M Series frames with the exception of the early type 46/7 B31 which has a smaller steering head.
Price is £40 per pair plus shipping at cost.
E mail me direct if you are interested...Ian

email (option): julie@wright52.plus.com

Now you tell me! Bugger! I've just rebuilt my forks, so I'm not pulling it apart just yet Ron

email (option): ronpier@talk21.com

OOPS ! .Sorry Ron...it slipped my mind at the time..I guess if you had been replacing the cups and cones it would have woken up my brain... .Fortunately I remembered to fit them on the WB30 and they are a great improvement...but you don't want to know that. ..Ian

email (option): julie@wright52.plus.com

They work really well on Commandos, you can't overtighten them, so no dented races and they seem impervious to water. Basically, they last forever. I only replace them if I'm having a frame painted.

One of the better ideas on the Commando but they never caught on and the Commando forums still have folk who want to replace them with taper rollers (which are not at all good in this application), presumably because they sound more exotic.

Are these a standard type ball bearing, or a thrust bearing? How are they not able to be affected by overtightening, or is there a tube between upper and lower bearing inner races?
Vince

Hi Vincent, They are a standard ball bearing. A tube could be fitted between them to prevent side loading the bearing but is not necessary if care is taken when fitting.
The steering stem cap nut is tightened only enough to bring the base of the top yoke into contact with the bearing...the yoke pinch bolt then locks everything into position.
When I fitted them to my WB30 I used a dab of threadlock Loctite on the cap nut to ensure it stayed in place.
Each set comes with fitting instructions....Ian

email (option): julie@wright52.plus.com

The Commando set-up has a slightly deeper bearing housing than necessary for the race and a centre tube. The crown nut is tightened to 15 lb/ft thus clamping the inner race and spacer tube, with the outer race finding its own location (it is a light interference in the headstock).

That is pretty much how the steering-head bearings are fitted to the later Buells. There is a specified torque for tightening the upper triple clamp and no spacer between the inner races.
In my experience it is a perfectly serviceable set-up. I have a Buell that is my daily runner for work and is just coming up to 100,000km and I plan to replace the bearings at that service as a preventative measure.
Sounds like more money will head into the M20 pit.

email (option): rays54@hotmail.com

I found the movement of the yokes to be very smooth when I fitted these to my WB30 and with the cup and cone set up on an M20 it is awkward to make adjustments once the front end is assembled, a fact noted in Ron Piers recent posting.
Also, as girder fork types do not have the adjustment sleeve fitted to later tele fork models, only the stem nut, they have a greater tendency to 'self adjust' during normal use.
The ball bearings neatly eliminate all these problems...
Interesting that Buell followed this line of thinking. As Rik said the commonly used taper roller set up is not actually the best one for this application...Ian

email (option): julie@wright52.plus.com

Ian, this the Buell set-up -


The one thing they have done is have a custom bearing that has an extended lip on one side - this goes to the top and the bottom against the triple clamps -


I am interested in seeing this set-up for the M20 - anyone else from Oz want to get a set and we can probably save a bit on shipping from the UK?

email (option): rays54@hotmail.com

Hi Ray...I already have one order from Australia..Michael Hughes from this forum. I don't know where in OZ he is as yet....Ian

email (option): julie@wright52.plus.com

Ian
I am having a swimming time in Brisbane QLD
Michael

email (option): nammech@hotmail.com

Hi Michael...I hope your on the high ground. I hear on the news it's moving South now...
Have you ever come across Lang Kidby?...he organises the 'Postie Bike' run and a lot of other stuff....Ian

email (option): julie@wright52.plus.com

Please excuse my ignorance, but why are taper rollers not so good for head bearings? I've fitted them to my B31 and Triton and have some for the M20 I am putting together. They seem OK on the B31 - better than the clapped out originals anyway
Cheers
Pete

email (option): petercomley@web.de

Hi Pete, Both ball and taper roller bearings are designed to bear both axial and radial loads. However, when loads are applied to the taper roller type the geometry of the design tends to force the roller from the race. The bearing track is constructed with a 'shoulder' in it to prevent this happening. The down side of this is that the force applied against the shoulder by the rollers results in higher friction values than those found in a ball bearing operating in the same conditions.
I couldn't put a value on the percentage difference between the two types under a given load so wouldn't like to say whether this is a 'meaningful' or 'theoretical' difference... never the less it is there..Ian

email (option): julie@wright52.plus.com

I was a bit of a Dresda fan in the 1970s (Dresda stickers and box section swing arms were something of a fashion statement). I was quite a good customer for their taper roller headset and swing arm bearings.

I found that in applications where a taper roller bearing cannot rotate through a full 360°, they don't seem to carry grease round. Whereas loose balls tend to circulate in the cups, on dissembling tapers I always found areas where they seemed to have pushed the grease out in front of them.

Caged balls have the advantage that they can be sealed (and they need to be). It doesn't seem to be possible to seal taper rollers in headstock applications as they are already taller than the standard bearings.

I just got fed up with replacing them every year due to localised fretting corrosion.

OK, gorrit! Learnt something new today (which probably means I will also forget something to make way for it )
Thanks!
Cheers
Pete

email (option): petercomley@web.de