1951 - 1952 A10 motor and Gearbox Wanted

[manxman]

I am looking for a motor and gearbox to start my  Golden Flash  project. I have a  1951 ZA7S frame and plungers and forks. Please email me with discription and pictures of what you have. Thanks  Bill

[a]

We would have gearboxs to suit, could do them as is (used) or in rebuilt condition ready to bolt in, but the postage could be a killer from Australia

[manxman]

Brett  I have found a couple gearboxes here in the USA? Thanks for the reply.  Bill

[duTch]

   You may already be aware, but keep in mind there are two different Plunger boxes (that I know of)- early and later. The casings are the 'same', but later ones have a rocker-cover type nut behind the kick start spindle in the outer cover, which is a lock-nut for the spring retainer inside. The covers are interchangeable (and the kick quadrant and ratchet gear-different spring), so possible to have different clusters inside..... .

 I know because I'm running an early box with later outer cover, and mis-matched it all without knowing what I was doing , ok until I needed to swap out a gear that was jumping...

[manxman]

Do you know when the change was made?  I am looking at two gearboxes, one has the nut the other does not. Thanks

[duTch]

 

Do you know when the change was made?  I am looking at two gearboxes, one has the nut the other does not. Thanks

 I don't know the changeover date, but I'm sure someone will. Maybe the early one was only on the Longstroke units .

 At least the odds be 50/50 

 ** Having said all that, is no knowing for sure what is inside either.....

[trevinoz]

What Dutch is talking about is the set-up for the kick start return spring.
The early boxes have a clock type flat section spring which anchors on a peg.
From 1953 the spring was changed to the round section and is anchored with a screw and nut through the outer cover.
Be also aware that the gear clusters from 1947 - 1950 are different to the later type and the gears can't be mixed and matched.
Complete sets can be used in any box.

[a]

see attached image of the two covers. Left is the plunger type, right is the swing arm type.. Note the differences around kickstarter area

[duTch]

 Thanks Trev- I felt I was already a bit long winded but committed and figured someone'd have to sort it out re; dates 
 The swing arm box has different selector arrangement, so isn't usable on a Plunger/Rigid, this is about two Plunger/Rigid framed boxes
 

[Sluggo]

Good to know on the 2 different type of early style gear boxs.  Assuming this also applies to a rigid frame model also using the semi unit engines?

Would appreciate a photo showing the 2 types. Will look this up in the parts books, but this is of interest to me mocking up several BSA projects right now with random parts that might not have been off the same bike.  (BITSA-Bits of This & That)

Would, per chance this also apply to M series gearboxs for the singles? And while I am hijacking a thread,  any tips on spotting the differences between a Cseries laydown style M type gearbox and a true 4 speed M series gearbox suitable for a rigid or plunger frame B33-B34.  Some of the late 40s and early 50s C10-c11-c12 seem to have a similar looking gearbox but much lighter duty and often times 3 speeds instead of 4 speeds.

[duTch]

 Can't help worth the non- A10/7 stuff,  but do actually have some digital 8x4 glossies with circles and arrows half ready to post due to another similar recent issue...I'll get onto it layer when I male it back to the Low Chaparral

[manxman]

What about clutches and primary sprockets? Can later pre unit parts be used on semi unit motors, gearboxes?

[Sluggo]

I *think* we are hijacking this guys thread a bit,, but a interchange thread for gearboxs (Shells, covers and asst parts.) and gears, primary parts etc all would be very useful for many.  I currently am sorting forks, triple trees and sliders for  a variety of british MCs currently and the variety of them for BSA Alone is staggering. I have parts books out in my storage area and its a daunting task, I might have some odds And ends for this lister but currently in a sort and catalog/inventory mode.
Sounds like he is hoping for a complete assy for motor and trans which will be challenging I suspect.

[duTch]

 Hey Sluggo- I might amicably point out that you just hijacked Manxman hijacking his own thread 

 Be back at the Crapparral after one more cold one, and will  add pics here, which I think is a relevant addition to this thread...pics pending

[Black Sheep]

Plunger bikes have a duplex primary chain and slipper tensioner. Later ones have the rather inferior single chain and tension is adjusted by moving the gearbox back and forward.