Plunger Engine Plates

[dsj666]

I received my bike ('54 plunger A10) in a series of boxes so am trying to identify what a have and what I need!
I'm sorting out what I need for mounting the engine to the frame.

Could anyone assist in identifying the items on the attached photo.

From the parts list picture I have the pair of P shaped front mounts but i'm confused as to whats required for the rear for a plunger.
Are the curved plates on the photo for a swing arm? perhaps the plunger engine mounts directly in the frame as the parts list seems to indicate?

Any ideas as to what the triangular plate is?

Thanks

[muskrat]

G'day dsj666.
Yes the curved plates are for a swing arm. The other bit looks familiar but can't remember from where.
The top picture of the parts list is how your plunger will be. The two front plates and spacer, 1 through bolt at the bottom of the motor, two bolts at the bottom rear of the gearbox and one at the top rear of the gearbox. Motor and gearbox is removed and installed in one big heavy lump!
Cheers

[chaterlea25]

Hi,
Those L plates are gearbox plates from a swing arm model
The other part is also swing arm, it goes from the frame and supports the long rear mudguard stay (non arrow head type stay)

John

[Swarfcut]

 
    Yup, the main picture is a plunger A10 crankcase complete with dynamo and front engine plates loosely installed in a single wheel fixed steering head frame.  The L plates are top and bottom swinging arm gearbox mounting plates and with a kink means they are useless to steady a rocking table so best to sell on.  From memory they fit on the drive side, and they are spurious and no use on a plunger bike. The single  plate rear  mudguard mounting ( S/A 1954 /c'59) is not a plunger part but this can steady the rocking table.

  Musky has explained the way the engine is mounted. Putting it into the frame will give you a hernia trying to do it in one go, it is a lot easier to assemble the gearbox and crankcase, fit that as a unit, then add the barrel and cylinder head.

  All the best sorting it out.

  Swarfy.

  PS  Any thoughts on the identity of the frame?

[dsj666]

Thanks all for the identification help...good job i didn't just rush in and get them all powder coated!!.. 

Swarfy.

  PS  Any thoughts on the identity of the frame?

Swarfy..what do you mean....identity?

[duTch]

 

.....Swarfy..what do you mean....identity?....

 I think he *maybe* means Frame # but not the whole # , I discovered that post '53 (?) have a steering lock lug at the top of the head-stock....conversely pre'54 don't (I think that's the changeover time)

 Make sure you have and use the spacer 67-4036, that goes between the top front lugs- I don't have one and couldn't find one, so just had to do a 'temporary' bodge....so far so good

[Swarfcut]

  Sorry folks, looks my attempt a humour was missed in the rush. "Installed in a fixed steering head frame " was referring to the barrow. The rocking table quip was intended to also be a bit  of light relief.

 Plunger frames with steering locks are rare, I  have only ever seen them on the last of the line, 1955/56.

  As duTch says, the spacer is often lost, but it is simply a snug fitting tube with a piece of sheet welded on which smooths the profile. Easy to make, or use the through stud position as a front footpeg mount.

 As usual it is always better to build in the rough first rather than damage your expensive paint job getting stuff to fit. Also as you have already found not everything is as it seems, so don't hesitate to ask when something holds up progress.

  If the bike came in large bits there is a good chance you will find lots of the nuts and bolts are missing. BSA used Whitworth threads in the soft alloy castings, and "Cycle" CEI (Cycle Engineers' Institute) threads for the majority of the other fixings.   A few cheap Whitworth and Cycle taps and dies will make life a lot easier and will be adequate for cleaning up your threads. Make sure you clean out the old jointing compound and crap from the bottom of blind holes, and be careful when tightening bolts in the soft alloy.

  Good Luck

  Swarfy.

 

[duTch]

 

Sorry folks, looks my attempt a humour was missed in the rush. "Installed in a fixed steering head frame " was referring to the barrow. The rocking table quip was intended to also be a bit  of light relief..........

 Thank far-queue for that- now I see it, I'm glad yo're about Swarfo, yea starting to makin me look good ....

 

....... Plunger frames with steering locks are rare, I  have only ever seen them on the last of the line, 1955/56......

 Guess I might've got lucky then....

 

....Easy to make, or use the through stud as a front footpeg mount.......

 Started to do that too, but realised the ride pozzy is already good enough

[Greybeard]

Plunger frames with steering locks are rare, I  have only ever seen them on the last of the line, 1955/56.

My '55 has a steering lock.

[dsj666]

I the light of the above I've just had a look through my boxes over the weekend..!!

I'm sure my frame is '54 and it would appear I have steering lock hole on the top yoke but nothing on the frame..!!!
So perhaps more mismatching of parts.. (although the yoke seems to fit perfectly)

[Sluggo]

on Preunit BSAs, I cannot say with 100% authority, But it would seem that there was a lot of parts bin engineering as sorting out project bikes and basket cases has required a lot of detective work trying to sort out what fits what, as well as "Was this factory?"
I spent a LOT of time earlier this year trying to sort out forks and triple trees and BSA alone consumed a lot of time and I still have questions.
Aside from deciphering the fork legs and variants, Top trees has been challenging.  In unit twins, there was 3 variations and then a final version meant as a univesal replacement that had me baffled for many days until I came across a clue that resolved it.  However in the mid 60s they use a drooping mustache top tree, But then reverted back to the preunit type.

Not everything has a casting number and part number, But in the early type, Preunit you have to look at width of the tree, Then look for instrument bracket bosses, locks and on the lower tree the steering stop cast features.

Some competition models dont have ANY bosses or holes, Some bikes HAVE bosses cast in but not machined, Some of the instrument bosses protrude quite high and others are flush or nearly so.   A nacelle model will in theory differ, as it doesnt use the instrument brackets, But I have a couple top trees that are baffling.  I also found it helps to look at as many other examples as possible, online and in person, Find someone with a known history bike and get close up pictures.  Frequently, The parts books are just a rough guide.

Rivet counters can go mad.   If you find a cross section of original and known history machines that are consistent, go with that,  Period advertising is probably the WORST examples to use, Some are airbrushed, Some were mocked up prototypes for photos. 

[MartinK]

You only need the items in the top picture. I installed my engine complete into the frame. There is a bolt that fixes the gearbox to the frame lug on the bottom of the vertical tube.