A10/GS swinging arm

[sprint]

Can somebody advise what the std distance should be across the outside faces of the A10/GS swinging arm pivot end with or without the bushes fitted?

I assume that when fitted that the end faces of the bushes stand slightly proud of the arm faces so that the ends of the arm do not rub on the frame plates?

According to Hailwood the distance between the frame plates should be between 9.383" and 9.378" http://bsa-a10.hailwood.com/1954abgoldstar.html

[muskrat]

G'day sprint. I'd fly with that. Just looked at mine with a steel rule and showed 9 3/8".
Cheers

[sprint]

G'day sprint. I'd fly with that. Just looked at mine with a steel rule and showed 9 3/8".
Cheers

Thanks for the reply. Is that across the arm faces alone or with bushes fitted?

Do you know if when the bushes fited the ends stand proud of the arm faces?

Just bought an arm on e-bay and it looks like the ends of the arm and bushes have been sawn off as it only measures 9 1/16" with the bush faces flush with the ends of the arm faces and as such it does not look like it is of any use?

Andy

[muskrat]

G'day Andy.
That was the frame between the plates.
I replaced the bushes with grease-able bronze bushes 23 years ago and don't have a spare swing arm with original ones fitted. They should protrude out from the swing arm equidistant and be clamped by the frame when the bolt is tightened.
Cheers

[beezermacc]

I've fitted quite a few sets of bushes in my time. When fitted correctly the inner sleeves of the bushes butt up against each other within the swinging arm tube; the outer sleeves press up against a shoulder in the swinging arm tube. The inner sleeves should protrude by about 2 mm to prevent the end of the swinging arm tube rubbing against the frame plates. When fitting the bushes you need to press them in by applying pressure on the outer sleeves until they are home against the shoulder in the swinging arm and you should use the swinging arm spindle in situ whilst doing the job so that the inner sleeves mate up against each other. The spacer which fits on the crankshaft and rotates within the crankshaft oil seal makes an ideally sized packer on the end of the bush whilst you're squeezing it in to prevent pressure on the inner sleeve. Beware of poor quality bushes on the market; if you have the later type swinging arm with hollow spindle there are bushes on the market (Wassells) which have inner sleeves too narrow for the spindle to fit through. There is a good description of fitting procedure on the Cheshire BSA website. I can supply the correct bushes if you need them. Hope that's helpful.

[sprint]

Thanks for the replies and advice.

With reference to the photos the width of the arm across the faces is about 9 2/16" to 9 3/16". The bushes do not protrude at all and the ends of the arm and bushes look to have been sawn off but by how much and if it is only one side?

Has anybody got a swinging arm that they can measure across the pivot arm faces to see what that should be?

Beezermacc, have you got a couple of bushes you can put together and then measure the distance between the inner and outer flange faces. That should then give the correct width of the pivot arm (inner faces should be flush) and the overall width with bushes fitted.

Andy

[bsa-bill]

Beware of poor quality bushes on the market

good point, the ones I got looked like the outer sleeve had been machined down (badly) one went in with a struggle the other (it's always the second one of anything that's wrong) would not go in, had to scrap them and bought ones from a good supplier  and they went in like a dream

bushes do not protrude at all and the ends of the arm and bushes look to have been sawn off.

They should be as beezermacc advised, it's possible the swinging arm has been out before and the brake through rod was seized in, then to remove it the rod was hacksawed through at both ends (together with some of the bush) - now how did I know that?
but bushes should have been replaced when the S/A was replaced

[beezermacc]

Hi 'sprint', picture attached. Total length is just under 240 mm. There is often a bit of damage and flexibility on the frame plates and they will compress onto the swinging arm spindle when you tighten it up. (n.b. I've made a correction to this post as I made a basic maths error - please forgive me - it is Christmas Day and I've already started on the whisky!)

[RichardL]

Sprint,

Here is what I think happened. The protruding ends of the inner sleeves got stuck in oversized holes in the plates. The previous owner couldn't get it apart and ran a saw between the plates and the ends of the swingarm, thus the inner sleeves cut flush and the saw marks on the swingarm ends. Assuming Beezermacc's measurements for the bushing are accurate (and I do), your swingarm might be 0.114" short. I am not sure this is a stopper as long as the outer sleeves protrude to represent the difference. Then, the ends of the inner sleeves need to butt againt the plates, not ride inside. If they slide all the way into the holes in the plates then the holes need refurbishing (for oversized or ovaled). One curious point: do the plates on your frame show saw marks or is the swingarm from a differentt bike?

Richard L.

[chaterlea25]

Hi Andy,
Well you got me to go to the shed on Christmas night, Do I ever get a day off       ????

Anyway the swing arm from My 55 B33 frame measures 9.25in (235mm) on the main tube
The overall length to the outside of the bushes is 9.375in

New bushes should restore the overall dimension but may leave a small shoulder of the outer bush protruding

You can always claim a refund and costs from the ebay seller as the arm did not match the description given

Regards
John

[RichardL]

Oops. I missed the point about buying on eBay. Anyway, I see 9-3/32" on your scale.

Richard L.

[beezermacc]

Hi Folks, please note I've made a correction to my previous post above. The figures are now correct, and note the comment about the whisky!

[sprint]

Thanks to all of you who have taken up any part of you festive time to respond and 'go to the shed' or otherwise to help. Replies and advise have been very helpful.

I guess that is the chance you take when you buy on e-bay. It would seem clear that the ends have been sawn through most likely for the reasons given. Disappointing because otherwise it is in good condition.

Swinging arm was bought as there is a problem with the one fitted to the RGS. When you tighten the drive side nut the spindle moves back on the offside. Clearly a bend somewhere in the arm so was hoping that a replacement would solve the problem?

I think I will send it back as it is not as described. Not knowing where the correct ends of the pivot arms should be I will never be confident that I have the correct chain alignment. There is a frame straightening company not too far away in Maidstone, so I think it it best to see if they can check the current arm and sort it.

[RichardL]

That sounds like an oval hole.