Poll

Sadly, I am colour deficient, and useless at making decisions upon colour choices. What colour should the BSA be in your opinion? (I withold the right for my wife to veto any of your choices) :-)

Black with red upholstry
1 (12.5%)
Cream sides, green bonnet and boot with black upholstry
2 (25%)
Dogsc0#k red (sorry, apparently it is a thing so my decorator colleague says) and black
0 (0%)
British Racing Green + black upholstry
3 (37.5%)
Cream and navy upholstry
2 (25%)

Total Members Voted: 8

Author Topic: BSA 3 wheeler.  (Read 5674 times)

RhysN

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Re: BSA 3 wheeler.
« Reply #15 on: 07 Mar 22, 03:34 pm »
I know it's not BSA, but there were a fairly good number of single cylinder Morgans, especially for record breaking. As small as 250cc!
Have a look on the Cyclekart club forum US based one) for "thinking outside the box" for a shaft drive. Link https://www.cyclekartclub.com/forum/cyclekart-tech-forum.2/1928-desoto-out-of-the-box-build.7257/.
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

Chris Brown

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Re: BSA 3 wheeler.
« Reply #16 on: 07 Mar 22, 06:11 pm »
The Yamaha Townmate, their equivalent of the Honda Cub, used shaft drive, so a rear wheel from one of those would suit.

David F-R

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Re: BSA 3 wheeler.
« Reply #17 on: 07 Mar 22, 09:39 pm »
The Yamaha Townmate, their equivalent of the Honda Cub, used shaft drive, so a rear wheel from one of those would suit.
And the 90 degree gearbox is quite cheap on ebay.
All good to know for the future, thanks Chris.
I'm not quite as green as I'm cabbage sounding.

Chris Brown

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Re: BSA 3 wheeler.
« Reply #18 on: 07 Mar 22, 11:13 pm »
The 90 degree gearbox is integral with the Townmate wheel, just need to get the complete assembly.

Chris

Jimr1999

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Re: BSA 3 wheeler.
« Reply #19 on: 09 Mar 22, 06:47 am »
... I suppose if one were to go down that route of front engine, shaft, final drive. It could be possible to put a 1:1 bevel box at the wheel end of the shaft and add a TAV to the output with chain final drive.
If you got the bevel box output shaft on the same rotational axis as a swing arm pivot, you could design a swing arm with two pivots (one either side of the box) and suspend the rear end with torsion bars made from socket set bars.

https://www.ebay.co.uk/itm/255047549642?hash=item3b6204c2ca:g:JJ4AAOSwulJg6AlH



... But complexity and weight are always just other things waiting to go wrong. :-)
I will keep it simple this time. ;-)
« Last Edit: 09 Mar 22, 06:50 am by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

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Re: BSA 3 wheeler.
« Reply #20 on: 11 Mar 22, 12:16 pm »
Been playing around with the rear end now the TAV and engine are here. Looks like I can just get it in behind the bulkhead if I have the TAV in this location.
Having had no experience of setting up a TAV, is their any difference in functionality in differing positions?
« Last Edit: 11 Mar 22, 12:43 pm by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

RhysN

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Re: BSA 3 wheeler.
« Reply #21 on: 11 Mar 22, 05:02 pm »
The TAV will work exactly the same in any orientation, except in some cases there is fouling between the engine and ribs on the face of the TAV, the TAV  can be safely gently massaged.
FWIW the current one I am building is vertically down.
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Jimr1999

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Re: BSA 3 wheeler.
« Reply #22 on: 12 Mar 22, 06:23 pm »
This week I have been mostly...

Getting the tyres and tubes on so the rims don't get too battered with all the fitting

Making the wooden chassis and gusseting it with ply (back end still to finalise now I have my motor, TAV and wheels)

Scratching my head on how to attach the back end and flukeing a discounted internal lintel at B+Q for a fiver that seems up to the job with a bit of grinding and drilling.

Grinding the lintel and wearing my cutting disc down to a nub and blowing a battery on the grinder

Scratching my head regarding the engine mounting plate and coming up with a cunning plan

Thinking hard about the spring set up

Persuading a colleague who turns to turn up some stuff for various spacers, bearing mounts

And having the occasional beer. Worked up until I get bits now - have brakes going around my head but I have a lot to do in the garden tomorrow so time to put the Kart on the back burner until I can get my hands on the drill press and a 15mm drill at work.
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

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Re: BSA 3 wheeler.
« Reply #23 on: 14 Mar 22, 04:52 pm »
Front uprights together today, thanks to a welder mate and a very accurate turner friend the Olite top hat bushes fit a treat.
I have bushed the spring hinges in nylon and hope that the friction when I nip them together damps the system slightly (who knows?)

Didn't turn out too far away from the CAD model
I had one hairy moment when I set the first one up caster forward by accident and the steering arm clashed with the hinge (wrong side! Doh!) but now I have something to tie the springs together. Yay!

« Last Edit: 14 Mar 22, 04:54 pm by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

David F-R

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Re: BSA 3 wheeler.
« Reply #24 on: 15 Mar 22, 09:48 am »
Looking very smart Jim.
I'm not quite as green as I'm cabbage sounding.

Jimr1999

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Re: BSA 3 wheeler.
« Reply #25 on: 20 Mar 22, 09:51 am »
Morning all.
 Been a busy weekend here and I have got to the point where things are coming together and in doing so creating their own challenges.
So far since the last update I have:

Added the spacers and bearings to the front wheels where I found out that they clashed with the Gemini front spindle/ steering arm if the disc mount side was put inwards but outwards cleared everything with 10mm to spare. I looked at Marek's build and it seemed that he had managed to overcome this somehow.

Glued a few more bits to the chassis to support the rear wheel fixtures and give it a tail for bodywork to stop at/ bulkhead support for seat fixing whilst gusseting the joins.

Mocked up the front end in scrap wood to determine spring length and worked out spacers necessary on the rear wheel to centralise things.

Attached loosely and thought about the rear pit bike hydraulic brake, which looks up to the task

drew up my mounting points for the rear wheel strengthening plates/ brake anchor/ chain tensioners.

Problems to solve...

1 The track is now perilously close to exactly a metre. This leaves no potential at all to adjust camber, especially out to negative camber.
Potential solution. 1. find a way to turn the wheels disc mounts in and gain 20mm ish 2. shorten the springs a little and live with it with the disc mounts (unused anyway) on the "wrong" side.

2 Torsional stiffness of the chassis. At this moment of incompleteness, the chassis is very twisty when loaded (I sat my 100kg frame on it for a bit) to the point it is a tilting three wheeler. not a good thing if you cant control the roll.
Solution is in the form of glue blocks, ply floor under slung, more glue blocks and a ply topper to the bit between my legs creating a sort of torque tube out of the chassis members (the original BSA had somthing similar except it was a tube). The bodywork should add a little stiffness too. (I speculate about how stiff this will end up, it is guesswork at the moment not having a stress analysing CAD program so the result may provide an "interesting" ride)

3 Steering. the controll arms are going to have to droop down a few degrees towards the steering arms from the Pitman arm. I envisage this providing a bit of bump steer but I can't imagine that it will be too significant???

I am pleased with how the front end is working out so far but I am sure it will throw me a few more challenges.
On with the day now.
... You can lead a horse to water, but a pencil must be lead.

RhysN

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Re: BSA 3 wheeler.
« Reply #26 on: 20 Mar 22, 04:27 pm »
Some potential answers
1, don't worry about width. I have not seen anyone get excited about others that don't measure.
2 Make the body as a plywood torsion box and make that an integral part of the whole thing. If you did that with 6mm ply the torsional stiffness will be immense, especially if you can complete as many sides of the box as possible. Front (where your feet will go can have  sides, front top and rear bulkhead with an opening enough to slide your legs through. Cockpit area, double up on the sides. Make the seat back integral to the side and bottom, and STRONG as you will lean on it to get in and out. Yes I have broken one to learn from.
3 Don't worry.
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

Jimr1999

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Re: BSA 3 wheeler.
« Reply #27 on: 20 Mar 22, 05:01 pm »
Thanks for that Rhys, always thinking too hard :-)
... You can lead a horse to water, but a pencil must be lead.

synthpunk

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Re: BSA 3 wheeler.
« Reply #28 on: 20 Mar 22, 08:53 pm »
I made my torsion box body up out of a series of smaller torsion boxes. Seat, rails, body sides, scuttle, seat back; etc… all out of 6mm ply. Built them as as true and straight as I could, Then bonded and bolted them all together. It is, as far as I can tell so far, immensely strong. I also filled all the void spaces within the lattice with expanding foam, which is definitely optional. All the metal spinny bits bolt on via subframes made from aluminium plate or extrusion.

It’s definitely a unibody rather than a monocoque. It’s an immensely pleasing object to have hiding in the garage.

Jimr1999

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Re: BSA 3 wheeler.
« Reply #29 on: 20 Mar 22, 09:04 pm »
Very nice Mr Synthpunk 😁
... You can lead a horse to water, but a pencil must be lead.