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Bsa a10 gearbox gears types
#795231 01/09/20 1:01 pm
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Hi i am confused, I need your help !.. i have two gearbox bolted to crankcase type, but they have different gears type....why ? please help me.

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Re: Bsa a10 gearbox gears types
gjchavezvargas #795233 01/09/20 2:16 pm
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Re: Bsa a10 gearbox gears types
gjchavezvargas #795241 01/09/20 4:12 pm
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I have an article from an April 1997 The Classic Motorcycle magazine that tells the story of a rider who bought a new early 1950 A10 and when he was not happy with the gearbox ratios he wrote to BSA to complain. Twice he took the machine to BSA for them to install different ratios to try. Apparently BSA staff were aware of the issue and were trying to solve it. I do not have the references to research any changes but I would bet that the STD set evolved during the production of that gearbox.

I do not know if any of the later swingarm A10 gears can be used in that box but it is possible.

Gordo


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Re: Bsa a10 gearbox gears types
Gordo in Comox #795242 01/09/20 4:44 pm
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thank., surely I look that post....I cant upload pics mm ?.... draganfly shows between gear 81 and 82 a trust washer,,, but my box have different 81 and 82 gears, THEY ARE NARROWED, I think they are wide ratio ?....the question is,,,, there are a trust washer between 81 and 82 narrowed gears ? ( number are from draganfly list,, sorry ).

PLEASE YOUR HELP FRIENDS...!

Last edited by gjchavezvargas; 01/09/20 5:41 pm.
Re: Bsa a10 gearbox gears types
gjchavezvargas #795256 01/09/20 7:56 pm
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Hi All
The earlier gearboxes have different engagement "dogs" to the swing arm models although apparently swopping over gear sets is possible
It was a common modification to fit the plunger model mainshaft to swing arm boxes in order to fit a Norton clutch
The 250cc 4 speed heavyweight box 1954/55 is also similar and bits will swop over but these have fewer engagement dogs on the gears
The late A and Gold Star gears are also a gearboxmaterial to the "lesser" models
The competition gears can also have different engagement dogs and gear widths to the standard boxes
All in all quite a minefield

John

Re: Bsa a10 gearbox gears types
gjchavezvargas #795257 01/09/20 8:06 pm
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In the Draganfly diagram the thrust washer is #89. I have attached the diagram for the swingarm gear box (very similar) and the thrust washer is #99. Without that washer the dogs of the #82 gear will go too far into #81. I would think that you would always need the washer. The thickness of the gears has little bearing on the ratios but the number of teeth will tell you what you have. I have also attached a shot of the later gearbox gears and the washer in between.

How do your gears compare with the ones I have shown?

Gordo


click to enlarge


[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]


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Re: Bsa a10 gearbox gears types
Gordo in Comox #795267 01/09/20 10:22 pm
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hi, thank you so much,,, I really investigate so hard in many many many post of you,,,,,my problem is i cant upload pics in this forum ( i dont understand why )......my email is [email protected] way i can send images for resolve the doubt.....I REALLY APPRECCIATE YOUR HELP, i want to put the gearbox tomorrow...thank you again !!

Last edited by gjchavezvargas; 01/09/20 10:23 pm.
Re: Bsa a10 gearbox gears types
gjchavezvargas #795269 01/09/20 10:36 pm
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https://www.a7a10.net/forum/index.php?action=dlattach;topic=11868.0;attach=36885;image...

in this draw i found the same type gears of mine,, look at D gear......question is,,,there is a thrust washer between thos layshaft gears ?

Re: Bsa a10 gearbox gears types
gjchavezvargas #795271 01/09/20 11:11 pm
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I cannot open that link. When you talk about the D gear are you using the letters from the BSA manuals? If so the D gear would be the second one over from the clutch side. The layshaft gears are B, D, F and H in that system. The mainshaft gears from the clutch side are A, C, E and G.

From what I can see there should be a thrust washer between the F and H gears.

Gordo

Last edited by Gordo in Comox; 01/09/20 11:20 pm.

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Re: Bsa a10 gearbox gears types
gjchavezvargas #795274 01/10/20 12:01 am
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try to open this image,,,https://www.a7a10.net/forum/index.php?action=dlattach;topic=11868.0;attach=36885;image.........,engagement dogs on my layshaft gears are different to draganfly shows.

Re: Bsa a10 gearbox gears types
gjchavezvargas #795275 01/10/20 12:02 am
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Re: Bsa a10 gearbox gears types
gjchavezvargas #795276 01/10/20 12:15 am
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https://www.draganfly.co.uk/index.php/component/hikashop/product/14229-

......this Layshaft 3rd gear is like mine,, see the dogs,,,,, there are thrust washer between this and Layshaft 1st gear, ??

Last edited by gjchavezvargas; 01/10/20 12:22 am.
Re: Bsa a10 gearbox gears types
gjchavezvargas #795284 01/10/20 3:57 am
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Based on the image in your last post above I would think that it looks something like the gear below on the right of the photo. This is not an F gear but a C gear out of a later STD gearbox for comparison only. I only show it for you to verify the type of dogs your gear has as they are hard to see in the photo you linked to. It they are the same then the H gear you have needs to look similar to the gear I have on the left. This is an A gear but it at least it shows you the type of mating gear you would need for engagement.

Click to enlarge

[Linked Image from i.postimg.cc]

These gears do not have a thrust washer for their engagement but I have no knowledge of the early boxes. Without seeing what you have it is hard help you out. There must be someone on the Forum with first hand knowledge of the early gearbox.

Good luck

Gordo


The roadside repairs make for the best post ride stories.
Re: Bsa a10 gearbox gears types
Gordo in Comox #795296 01/10/20 11:58 am
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Gordo in Comox, THANK YOU SO MUCH, !! ,, yes, now you understand me,,,the engagement dog on my 1st and 3 rd layshaft are like you shows ( i don know how upload pics here ),,,i thinnk my gearbox are earlier box,,,,,so....you resolve my doubts about thrust washer.....today reasemble that box...

THANK YOU SO MUCH FRIENDS !


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