Author Topic: fork shroud gap  (Read 328 times)

Offline tomkilde

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fork shroud gap
« on: 02.06. 2021 02:08 »
After powder coating my yokes, I re-assembled them with new tapered bearings.  I also installed brand new "made in England" fork shrouds, but was disappointed to see large gaps between the top yoke and the shrouds - about 1/4".  I assume there should be no gap at all.  The new bearings are pressed in as far as they will go, so I suspect the shrouds are not correctly fabricated.  To verify this, can someone tell me what the correct distance between the upper and lower yokes should be?  (It's a 1961 model.)  I have no old shrouds to compare the new ones to.
1958 BSA A10 Super Rocket

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Re: fork shroud gap
« Reply #1 on: 02.06. 2021 15:22 »
Sorry to be the bearer of bad news, but you have the wrong shrouds. Your shrouds are A65 shrouds. As you have discovered they are different dimensionally. For identification purposes A10 fork shrouds have a single round headlamp fixing hole. Yours have a slotted headlamp fixing. Many part sellers advertise them as being a universal fitment for unit and pre unit twins. Unfortunately they are not.

Offline Swarfcut

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Re: fork shroud gap
« Reply #2 on: 02.06. 2021 17:04 »
 For comparison a handy pair of plain (no ears) shrouds are 380mm long, Centre of lower yoke bolts is 176mm from the tapered top end. Just hope mine will fit when the time comes......They were offered as A10. As always, these old original parts carry an element of uncertainty, but look kosher enough.

 New taper bearings may not match the original  cup and cone set up and could account for the difference. Short term a couple of custom spacers can fake it well enough.

 Swarfy.

Online Rex

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Re: fork shroud gap
« Reply #3 on: 02.06. 2021 19:15 »
  New taper bearings may not match the original  cup and cone set up and could account for the difference. Short term a couple of custom spacers can fake it well enough.
 Swarfy.

I've always found this to be true too, and one good reason not to change to taper rollers.
Not much point in having bearings where the rollers are visible and able to collect grit in the lube.

Offline RichardL

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Re: fork shroud gap
« Reply #4 on: 03.06. 2021 00:00 »
Without going into a long-winded story of how it happened to me, I had a very similar situation. After paying for the wrong ears and having them chromed, I decided I could do with an A50/65 top yoke, like this: https://www.ebay.co.uk/itm/223420567105?hash=item3404e74e41:g:J9QAAOSwWhVbwoev. Having gone through that, I could be wrong, but I'm thinking there is something else going on with your shrouds, because A10 ears/shrouds are almost exactly an inch higher, as shown in the photo. What, exactly, is going on with your yoke, bearing or shrouds, I'm not sure. I bought the right ears for the day I decide to return my ears and top yoke to genuine A10.

Richard L.



 
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Offline RichardL

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Re: fork shroud gap
« Reply #5 on: 03.06. 2021 00:09 »
I just reinstalled my ball-bearing steering head bearings. The dust cap is above the frame ledge (for lack of a better name) by about 0.190". Yours looks similar, so hard to blame taper bearings for raising the yoke too high.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline RichardL

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Re: fork shroud gap
« Reply #6 on: 03.06. 2021 00:19 »
I've confirmed Swarfy's 176mm on an original set of no-ear shrouds from my A7. Can't tell from the pictures, but is it possible the bottom tapered bearing is protruding, or maybe the lower yoke just needs to be pulled up farther via the stem?

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online bsa-bill

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Re: fork shroud gap
« Reply #7 on: 03.06. 2021 11:42 »
I have replaced the bearings on both my bikes and yes there is a gap, but I am not going to get in a flap about a small amount of roller exposed to fresh air on a bearing that moves only a small amount and at a snail's pace,
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline RichardL

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Re: fork shroud gap
« Reply #8 on: 03.06. 2021 14:24 »
Tom,

I just realized you never got your original question answered. On my A7 in-the-works (ball-bearing races), center-to-center distance between yokes is 7-3/8".

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline tomkilde

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Re: fork shroud gap
« Reply #9 on: 03.06. 2021 15:47 »
Thanks all for the info and advice.  The headlight mounting holes on my reproduction shrouds are indeed "wrong" (thanks for that observation Swarfy, I had not noticed), but all the dimensions are correct - 15" overall length, 7" from the bolt center to the top of the shroud, and 7" between ears.  I suppose I will have to disassemble the yokes and take a closer look at the new bearings.  It seems like everything on this project is two steps forward and one step back...

Burton's and Draganfly are the only shops I can find that carry shrouds with the correct round headlight holes, but both are currently out of stock.

1958 BSA A10 Super Rocket

Online Rex

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Re: fork shroud gap
« Reply #10 on: 03.06. 2021 16:18 »
I have replaced the bearings on both my bikes and yes there is a gap, but I am not going to get in a flap about a small amount of roller exposed to fresh air on a bearing that moves only a small amount and at a snail's pace,

Fresh air's no problem, it's just the amount of shit grit and dust it's carrying with it.

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Re: fork shroud gap
« Reply #11 on: 04.06. 2021 16:21 »
I too have fitted taper roller steering head bearings. I bought mine from SRM and had absolutely no dimensional issues. The bearings fit perfectly and do not sit proud, and there are no gaps or miss alignments with with the shrouds. I bought my shrouds from George Prew.

Offline tomkilde

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Re: fork shroud gap
« Reply #12 on: 05.06. 2021 22:07 »
I may have found the problem.  The part number cast into my top yoke is 65-5448, which apparently is not correct for a 1961 A10.  Visually, it looks like the correct part (42-5035 or 5036) but there may be some slight difference in geometry causing the gaps?
1958 BSA A10 Super Rocket

Offline Swarfcut

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Re: fork shroud gap
« Reply #13 on: 05.06. 2021 22:28 »
 Tom. I'll congratulate you on being the owner of a top yoke Forging 65 5448, being the top yoke from an A or B Series Rigid/Plunger. Model years 1954 onwards, with steering lock. Almost the same as a S/A part but not quite...

 Thanks also to Drags, for their comprehensive online parts catalogue........

 Swarfy.