Author Topic: Swing arm poser  (Read 356 times)

Offline PDMiller

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Swing arm poser
« on: 19.01. 2019 19:36 »
Evening all from a very chilly Northumberland. It's brass monkey temps in the man cave and flushed with a few minor successes I decided to trial fit the swing arm and rear wheel. I never know what this rebuild is going to throw at me next but it looks as though the swing arm and wheel don't match *razz*. I think I have a swing arm from a full width brake model and the wheel I'm using is obviously a half width crinkle hub with left hand brake drum. As can be seen in the pic the rear sprocket is almost fouling the chain guard bracket and there is no brake anchor point on that side.
Is there any reason why I can't fabricate and weld an anchor point and chop off the chain guard mounting to replace it with the gold star type? I found some very useful drawings on this forum with dimensions of both types.
The next question is: Will the chrome brake plates that are available for around £75 on Ebay fit my 7" drum?
Any advice most welcome and in the meantime I'll sink a cool beer and contemplate why, in my dotage do I get into these ridiculous situations.

Pete

Online bsa-bill

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Re: Swing arm poser
« Reply #1 on: 19.01. 2019 19:45 »
One Northumbrian to another, which part of Northumberland do you inhabit?
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

Online Brian

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Re: Swing arm poser
« Reply #2 on: 19.01. 2019 19:50 »
The wheel you have is from an A7 plunger model.

I think it will have 47 teeth on the sprocket, you need 42.

Anything can be made to fit but it will take some work.

Offline PDMiller

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Re: Swing arm poser
« Reply #3 on: 19.01. 2019 20:04 »
Hi BSABill I'm in Widdrington just outside Morpeth. Going to dive out into the garage now to count the teeth on my sprocket *eek*.
The sprocket has 49 teeth Brian so guess it must be for sidecar use. Oh well something else to worry about *sad2*

Online bsa-bill

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Re: Swing arm poser
« Reply #4 on: 19.01. 2019 22:11 »
Quote
Hi BSABill I'm in Widdrington

Know Widdringtom, used to go there on occasion to pick up a Dixon Edwards (sadly no longer with us), I lived at Stannington before we moved up here early sixties (15 miles south of Berwick), went to school in Morpeth, yes still got fond memories of that area
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 PDMiller

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Re: Swing arm poser
« Reply #5 on: 20.01. 2019 09:38 »
Hi Bill
Still a few enthusiastic old bike nuts here (must be something in the water)

This is a new learning experience for me, I've got a shed full of Triumphs and AMCs but this is the first BSA for nearly half a century  *eek*. I'd like to fit the chrome brake plate and now that I know I need a different drum / sprocket hopefully I'll be able to find something that allows me to do both.        More research needed.

Roads icy here today so the bikes are staying firmly in the shed. ;)

Offline Swarfcut

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Re: Swing arm poser
« Reply #6 on: 20.01. 2019 10:45 »
Hi PD...Looks like your hub and wheel were just there to stop the mudguard dragging in the dirt on the day of purchase.

  Well, here's the good news as I see it.   That 49 tooth "dinner plate" sprocket and matching brake plate are from an earlier plunger framed bike. 49 is sidecar gearing. Solo is 42. They are no good to you, but saleable in the grand scheme of things. Your choice now depends on how your frame is set up for the rear brake pedal. Left hand rod, go with 1954/55 rear hub, you may need to add a torque arm mount, depends on what is left on your swinging arm.  Hollow S/A spindle, choice is Ariel Hubs, rarer, only used for a short time, or later cast iron full width, both plus a rear wheel to suit. Crossover shaft, pedal, cable etc will add to the complexity and expense. lots of comment on brake pedal choices on the forum in recent weeks.

  I reckon your present wheel will fit, maybe with just the correct spindle, plus the odd custom spacer, if you stick with the early half width S/A brake.  Probably ended up with 49 teeth in a misguided attempt at scrambler gearing.

 Swarfy.

 Swarfy

Online duTch

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Re: Swing arm poser
« Reply #7 on: 20.01. 2019 11:15 »

 Contrary to the assumption the chainwheel being from a Plunger model (and probably is), as it's obviously just on for the sale, I'm fairly sure the swingarm chainwheel is almost identical to the Plunger ones except for the size of the hole for the bearing to backing plate spacer(Hub Collar), as they use different spacers.....so unless you want to do hill-climbs it maybe still no good anyway- just sayin'  *beer*

 ** and in addition it's probable no sidecar gearing was available for early swingarm models anyway
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Swarfcut

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Re: Swing arm poser
« Reply #8 on: 20.01. 2019 12:45 »
Dutch.. The backplate pictured has the cut out for the plate anchor, which is part of the forging on the spindle mounts on the plunger models. I do not know if early S/A rear spindle lugs had this anchor, allowing the use of the plunger backplate. My parts book only shows a half width 54/55 hub which has a strap type torque stay which attaches to the S/A .

  PD.... No alternative rear drum sprocket listed for the year, but a choice of 18 or 19 teeth available for the gearbox. Comparing plunger and the early S/A, Swing Arm drum has a smaller central hole, no hub collar, and from the parts list the ballrace is different. Plunger is 89 3022, S/A 65 5883. The spindle designs are also different.

 Swarfy.

Offline PDMiller

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Re: Swing arm poser
« Reply #9 on: 20.01. 2019 14:56 »
Hi PD...Looks like your hub and wheel were just there to stop the mudguard dragging in the dirt on the day of purchase.
You're dead right Swarfy. If I hadn't bought this bike on Fleabay I'd have run a mile but to be honest it gets me out from under the Wife's feet and I'm enjoying the challenge.

I'd like to stick to the left hand brake if possible. No doubt the brake pedal will be a problem because there doesn't seem to be anywhere to fit it but that's for another day.   Finding an excellent drawing with dimensions on this forum I'm going to chop off the old chain guard mountings and weld on the brake torque bracket. I would like to get rid of the existing brake plate and replace it with a chrome one if possible. The swing arm has the hollow tube and I find this hard to believe but the bushes seem to be ok.     Making up spacers is not a problem, I have a trusty old lathe ,Almost as old as me and a big box of bits of stuff that'll come in handy one day.
Thanks for the help and advice, much appreciated

Pete

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Re: Swing arm poser
« Reply #10 on: 20.01. 2019 19:23 »

 
Quote
........... Comparing plunger and the early S/A, Swing Arm drum has a smaller central hole, no hub collar, and from the parts list the ballrace is different. ......

 Swafie- there's no doubt about the brake plate being from a Plunger, but the S/Arm list I have shows # 45 is a 'Hub Collar' for the chainwheel-Brake plate Part #67-6032, The way I see it, is if it isn't there the plate will be sandwiched and the wheel won't go around.


 I've not had a swing arm model of this setup, but had enough trouble with an A65 chainwheel on a '54/5 hub on my Plunger.....it worked, but not ideal
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline Swarfcut

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Re: Swing arm poser
« Reply #11 on: 20.01. 2019 19:53 »
      Sorry folks, we are talking two different collars. The plunger drum has a steel ring which fits reasonably closely around the spindle and is a press fit in the centre of the drum, part no 67 6078  Hub collar L/H. This collar rotates as its in the drum.

  The early 1954/55 half width S/A hub also has a spacer, 67 6032 as correctly indicated by duTch,  also described as Rear Hub Collar. So there we are, a recipe for confusion.

   duTch is right, the spacer 67 6032 is firmly sandwiched between the backplate and the inner bearing race and does not rotate, spacing the drum away from the backplate. Without it the drum will lock against the backplate.

 Swarfy

Offline RayC10

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Re: Swing arm poser
« Reply #12 on: 21.01. 2019 17:32 »
If you like, you can get new 42 tooth sprickets for S/A (Burton bike bits et al) or if you wanted to gear her down, a 46 tooth is available (A7). I have a 46 tooth you can have if ever you are in Norfolk, bought it by mistake, I have a plunger and as has been mentioned earlier, the spindle stub is smaller ( bearing also 2" OD rather than 2 1/4 on the plunger). Ablolutly sure there are enough bits around to build your wheel. I expect the spindle has to be different from the plunger type an' all. Cheers.

Offline kiwipom

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Re: Swing arm poser
« Reply #13 on: 21.01. 2019 20:04 »
If you like, you can get new 42 tooth sprickets for S/A (Burton bike bits et al) or if you wanted to gear her down, a 46 tooth is available (A7). I have a 46 tooth you can have if ever you are in Norfolk, bought it by mistake, I have a plunger and as has been mentioned earlier, the spindle stub is smaller ( bearing also 2" OD rather than 2 1/4 on the plunger). Ablolutly sure there are enough bits around to build your wheel. I expect the spindle has to be different from the plunger type an' all. Cheers.

hi guys, learnt a new word today, (42 tooth sprickets) cheers
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Offline PDMiller

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Re: Swing arm poser
« Reply #14 on: 21.01. 2019 20:16 »
Thanks for the offer Ray. I'm just about to order a 42 tooth and still hoping I can get a chrome back plate to fit it.  Thanks again for the offer and advice.
Cheers
Pete