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Taper headstock bearings?
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Rich_T
Dumfries & Galloway
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March 28, 2019 - 2:21 pm
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I've had a search borh on here and google but haven't found anything conclusive. So, has anyone come across any taper bearings that would fit the D14 headstock?

Thanks 

Rich 

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Sponge
Lancashire (A chip shop somewhere near Preston)
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March 28, 2019 - 2:52 pm
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Hi Rich,

SRM Engineering in Aberystwyth used to sell a taper-roller bearing kit for the Bantam Swinging arm models.  I bought a set about 20 years ago and fitted them to my B175 - an easy enough job but they made such a difference to the bike - it was amazing how good the steering felt.   

I still have the bike, and the taper-roller bearings still in use after 20 years.  It is till the most positive bike to ride.

I asked SRM if they could still produce these but they didn't seem interested. Probably because us Bantam bikers are a bit tight and wouldn't pay out the money even if SRM did start to re-produce them.  They might still have the drawings / designs. If enough of us pester them they might take an interest.

I had some headstock taper-roller bearings made up specially for my trials bike. An engineering firm in Lancashire that used to make gun barrels made  them up and did a super job. It wasn't cheap but it was good. However that engineering firm has now gone out of business and the workshop is now a brewery.   ( more beer - less engineering - the story of my life ).  

There must be somebody out there who can produce a kit such as this (Rex Caunt ?), but it all depends upon weather there is a market I suppose. I would buy them.  

Sponge

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Rich_T
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March 28, 2019 - 3:49 pm
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Thanks for that sponge,  it does surprise me that someone like RC doesn't do them but as you say there may not be enough of a market that would pay the price. 

Rich 

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Sponge
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March 28, 2019 - 8:50 pm
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Hi Rich,

If Rex was interested in making up these taper roller bearings then I would be happy to take the bike over for him to measure them up etc.  I have thought about getting a batch made up myself but I do not know anybody who can make bearings.  Perhaps it only needs somebody who is handy with a lathe to machine some commercially available bearings down to size.  As Roger Waters said - 'Is there anybody out there ?' 

The difference they make to handling and steering is remarkable.  

Sponge

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Rich_T
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March 28, 2019 - 10:30 pm
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Turning some existing ones down could be a possibility and I ll have to have a look into it. I do have a lathe but its not that good (neithers the operator). Perhaps this is the excuse to buy a better one....

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GlenAnderson
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March 29, 2019 - 6:10 am
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You can’t turn bearing races down in a lathe; they’re too hard. 

If commercially available ones aren’t the right size, then getting an engineering workshop with a cylindrical grinder to modify some is a possibility, but they’d have to make a mandrel to hold it and one-off old-school engineering isn’t cheap. You’re unlikely to find a hobby machinist with the capability to do the job.

If you wanted a quantity, then you’d probably be better commissioning a batch from a manufacturer rather than modifying something. It’s one of those tasks that one item will cost “x”, ten items will cost “2x” and a hundred “3x”. 

If you take a set of standard races, assemble them with their balls and measure OD, ID and thickness, you have all the information you need to take to a bearing factor and ask the question. 

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Sponge
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March 29, 2019 - 8:09 am
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Thanks for that. Looks like we might have a plan going forward.   

Sponge 

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stubaker58
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March 29, 2019 - 2:28 pm
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I’d be up for a set, it would give me the reason I need to strip down the front end and smarten it up a bit!

D7/14 hybrid (4 speed with D7 crank etc.) on the road, D10 Bushman awaiting rebuilding.

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Rich_T
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March 29, 2019 - 3:02 pm
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Ive ordered a coyple of bearings with the correct inside diameters and once they arrive I'll see if they can be ground down.

Another option for the lower one would be to haver the headstock machined out by around 0.5mm as I can find one with a 27mm inner and 48mm outer. The same could work for the upper using the same bearing but it would need a bush to step it down from 27mm to 25.4mm.

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SpacedMarine
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March 29, 2019 - 9:55 pm
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Be interested to see how you get on with this.Ive had the forks out but not the headstock so I don't even know how they're held in to be honest.Ive just got myself a lathe and am looking for a few projects to justify it😁I'm guessing your only have to take a bit off the outer cup then tap it in gently maybe pop in the freezer overnight. im guessing you may have to make a tapered mandrell to hold in the lathe and put a thread on so you can hold it on with a nut?

I've got some bronze to knock some gearbox bushes up but taper roller headstock bearings sounds an all together more exciting prospect!

20190329_220446-1.jpg

Just sat around in the truck so I drew a picture 😂

What's 7/16 in mm again?

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Sydney
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September 2, 2019 - 9:21 pm
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Does anyone know if these will fit a 1952 D1 headstock?

** Please log in to view **

** Please log in to view ** - I haven't checked for the lip on mine yet.

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Mick W
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September 2, 2019 - 10:06 pm
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The best thing you can do is contact Draganfly and ask them the question. Looking at the information available I would say they fit the D1 and D3.

If you do get a definitive answer perhaps you would kindly let the forum know.

Mick

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September 3, 2019 - 8:17 am
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Will do.

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mike p5xbx
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September 3, 2019 - 4:12 pm
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They probably will on an early bike as the top and bottom bearings were the same
But best to check that there is not a step at the bottom of the stem which is probably what Dragonfly will tell you
I think D5 onwards had the step but not 100% sure of that

bearing-step.jpg

sp_PlupAttachments Attachments

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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two-stroke
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September 3, 2019 - 5:11 pm
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up to 55 used same tipe top and bottom same as later top type dragonfly 2x 65-5319TR

55 on all modles used 2 difrent coans top dragonfly 65-5319TR nd bottom becuse of stem step dragonfly 40-5027TR

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SpacedMarine
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September 3, 2019 - 10:33 pm
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Just wondering if the column is pressed into the yoke?Maybe you could press it out and get someone to turn it down a bit?Then have taper roller bearings!If not forget I said anything read-manual

What's 7/16 in mm again?

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FrankG
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September 3, 2019 - 11:10 pm
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Hi, if you know someone with a reasonable size lathe it could be done in a 4 jaw chuck without pressing it out.

Frank

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mike p5xbx
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September 3, 2019 - 11:56 pm
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Im guessing that the addition of the step part was to increase the rigidity at the join to the Bottom Yoke
and stop stem from falling out laugh

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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cocorico
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September 4, 2019 - 7:53 am
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mike p5xbx said
Im guessing that the addition of the step part was to increase the rigidity at the join to the Bottom Yoke
and stop stem from falling out laugh  

And as seems to be the question with other Bantam 'oddities' - BSA must have done it for a reason...

1956 D3 running, lights to sort. 7 other bikes in the Barn. 1950 D1 engine being rebuilt (slowly).

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Ringting
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September 18, 2019 - 10:42 pm
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May be to make it easier to fit the bearing. Otherwise the bearing would be a tight fit and need pressing on for the whole length of the steering tube.

D1, D14/4, Guzzi LeMans, Triumph Trident 900, Maserati 160 t4. Mk1 Mini Traveller, Berkeley T60.

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