Author Topic: 1951 A7 frame suff (rear plungers, centre stand)  (Read 502 times)

Online Rex

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Couple more quickies, if I may-

1) deleted
2) is there a dodge for removing the rear plungers? The service notes say to use a tool but sometimes there's tips for getting around buying the once-in-a-lifetime service tools.
3) did the centre stand originally have a "foot" sticking out to the left to push down on when struggling to get the bike on the stand?
Thanks.

Offline morris

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #1 on: 23.10. 2017 20:45 »
An M10 threaded rod, some big washers and a couple of nuts will do the trick.
Take out the centre tube, slide the lot a bit aside until you can get the rod through the hole. A washer and nut top and bottom and the complete setup can be slid out. Mounting them is the reverse of the above.
Be careful to keep your face out of the way because if they jump out, they’ll jump out with a crazy speed.
The centre stand has a short “foot” to help get the bike on the stand
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
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Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #2 on: 23.10. 2017 21:21 »
Thanks!

Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #3 on: 26.10. 2017 21:42 »
An M10 threaded rod, some big washers and a couple of nuts will do the trick.
Take out the centre tube, slide the lot a bit aside until you can get the rod through the hole. A washer and nut top and bottom and the complete setup can be slid out. Mounting them is the reverse of the above.
Be careful to keep your face out of the way because if they jump out, they’ll jump out with a crazy speed.
The centre stand has a short “foot” to help get the bike on the stand

Morris, how do I take out the centre tube? It's been given a good dose of release oil and the three clamping points opened slightly with fox wedges, but it's still tight. I guess the original BSA tool would have threaded into the top of the tube and been used to force it down through and out, but any light taps applied to the top of the tube will tend to nause the top threads beyond use. Am I missing something obvious?

Online JulianS

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #4 on: 26.10. 2017 22:33 »
The column and bearing sleeve are notched for the pinch bolts so you need to completely remove them. See the service sheet below.

Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #5 on: 27.10. 2017 13:13 »
I should have been more specific as those bolts have been removed already, but I just wanted more info on getting a purchase on the centre-tube. If I punch it out, being thin-walled and threaded it'll be destroyed, which is something I want to avoid.

Online Greybeard

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #6 on: 27.10. 2017 15:26 »
I should have been more specific as those bolts have been removed already, but I just wanted more info on getting a purchase on the centre-tube. If I punch it out, being thin-walled and threaded it'll be destroyed, which is something I want to avoid.

There is a blanking piece in the bottom of the column. Don't ask me how I discovered that! Take care.

A bit of heat may help you. It usually does.

Health & Safety personnel look away now.
When I disassembled my plungers, after removing that column I just levered the assembly out of the frame with a tyre lever. The thing shot out and bits flew around the shed. It's was very lucky that non of the bits came my way! On the other side I did the same thing but tied a rope through the hole where the column normally goes. This kept bits together on the hoist. Still quite exciting though! Just be careful with loaded springs.

When I reassembled the plungers I made up a piece of thread rod with large roofers washers which worked great except at the end while getting the large washers out from between the frame and the spring shrouds I scratched the new paintwork on the shrouds!

Last year I decided to do something about the scratches. When reassembling I strapped the bike down and used my hydraulic car trolley jack to compress the assemblies enough to just slide them into position. No damage done to the paintwork, or me.
Here's the thread:  https://goo.gl/YH3Ymi

Offline morris

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #7 on: 27.10. 2017 19:33 »
If I remember well, I unscrewed the aluminium  top nuts a couple of turns and gave them a couple of knocks with a plastic hammer until the shafts worked loose. I then knocked them out entirely with the aid of a long aluminium drift.
In the worst case you’ll damage one of the top nuts, but they are readily available and not expensive.
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium

Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #8 on: 27.10. 2017 21:31 »
Yeah, I think I'll grind the flanges off and wind both caps into one tube (for max strength) and use to that to push on, then buy two new caps (+ whatever else needs renewing when it's apart!)
Thank you Morris.

Online Greybeard

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #9 on: 28.10. 2017 08:21 »
I bought new chromed steel top caps from Draganfly.

Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #10 on: 28.10. 2017 09:49 »
Always my first port of call.... ;)

Online Rex

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Re: 1951 A7 frame suff (rear plungers, centre stand)
« Reply #11 on: 31.10. 2017 20:53 »
The old caps had their flanges removed and then reinserted back into the columns. The rear frame half was placed on two hardwood baulks under the frame rails and the caps given a tap or two with a dead-blow persuader, and it all went very well.
I put the frame on it's side on an old mat I have, the end was wrapped over the plunger assembly, and with my foot holding the plunger still, the frame was pulled away.
A slight muffled click as the plungers came free and that was it.
Thanks for all the advice.