Author Topic: Gearbox ID  (Read 562 times)

Offline Peter in Aus

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Gearbox ID
« on: 31.07. 2018 10:07 »
Hi, can anyone ID this gearbox?  It has an “R” stamped on it where the “STD” is usually stamped; it is a bolt on box so must be off an A Ser. Plunger.
The bit that is puzzling me is it had swinging arm main shaft with the tapper and key way for the clutch spigot. At least I think these were fitted only to the swinging arm models?
There is some other markings on the large mounting bracket, bit hard to read but it looks like “2/OB”
I obtained this box along with another box and some other bits so don’t know what they are off or history.
Peter

Busselton West Australia
49 A7 longstroke
58 A10  SA

Offline Peter in Aus

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Re: Gearbox ID
« Reply #1 on: 02.08. 2018 02:29 »
Looks like I"v asked a bum question? *sad2*

Busselton West Australia
49 A7 longstroke
58 A10  SA

Offline duTch

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Re: Gearbox ID
« Reply #2 on: 02.08. 2018 10:02 »

 Dunno Pete- I'm not sure that Plunger cases were stamped in general- if I remember tomorrow, I'll have a look at the ones I have....I think an 'R' usually refers to needle rollers in either the layshaft or the sleeve gear or both, but they are (generally) only in Swing Arm models...sooo um *dunno*
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 Peter in Aus

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Re: Gearbox ID
« Reply #3 on: 02.08. 2018 11:31 »
Thanks Dutch for the reply, I'm beginning to think it has had a very checked past.

Busselton West Australia
49 A7 longstroke
58 A10  SA

Online muskrat

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Re: Gearbox ID
« Reply #4 on: 02.08. 2018 12:00 »
G'day Peter.
Both my gearboxes (plunger & s/s) are stamped std. The mainshafts are interchangeable so they may have fitted a 4 spring clutch to a plunger  *dunno*
I think R meant needle rollers on the layshaft and RRT2 was needle rollers on both shafts. I may be wrong (I'm sure someone will delight in putting me right).
Cheers
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Online Greybeard

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Re: Gearbox ID
« Reply #5 on: 02.08. 2018 14:07 »
I just had a look at my box. I cannot see anything on the clutch lever area, (your second picture). On the front of the top mounting, there is a B with 20 under that.

Online morris

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Re: Gearbox ID
« Reply #6 on: 02.08. 2018 20:57 »
The mainshafts are interchangeable so they may have fitted a 4 spring clutch to a plunger  *dunno*

The 4 spring clutch sprocket is to big for the plunger case.
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Offline chaterlea25

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Re: Gearbox ID
« Reply #7 on: 03.08. 2018 00:08 »
Hi All,
R, RR, SC. TRI, ASC and so on indicate the gear ratios fitted

T (for Torrington) indicates needle roler bearing layshaft. T2 indicates that a needle roller bearing is also fitted to the mainshaft high speed gear

Peter,
Probably someone wanted the splined shaft  so they could fit a Norton clutch to a swing arm gearbox
Then fitted the S/A shaft in the plunger box and flogged it on
(I have seen this happen *ex* *ex*)

John
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Offline duTch

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Re: Gearbox ID
« Reply #8 on: 03.08. 2018 06:22 »

 
Quote
Probably someone wanted the splined shaft  so they could fit a Norton clutch to a swing arm gearbox
Then fitted the S/A shaft in the plunger box and flogged it on
(I have seen this happen *ex* *ex*)

 I nearly did that,  but it was going tho be more than I could cope with at the time so standard insanity prevailed... *eek*

 I had a look at the four unused cases I have and three have what looks like variations of 'B 2 0' on the to rear lug, and the fourth has '55' on the inner (biscuit) case and a stamp (V98)? on the outer,  keeping in mind they are all mix-ups of early flat spring outers and
composites of other bits and pieces-except for one (kinda)

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 a

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Re: Gearbox ID
« Reply #9 on: 03.08. 2018 07:28 »
No Doubt you and everyone else already knows of this chart outlining the normal stamping and gears etc.
https://mikesclassiccyclespares.com/bsagearchart/ But that is for the Swing Arm style box
The plunger/Rigid did not use these markings, as discussed in this earlier post
https://www.a7a10.net/forum/index.php?topic=6018.0
we have 5 plungers/rigids here all with a different markings on the "Sandwich" plate....


Online BSA_54A10

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Re: Gearbox ID
« Reply #10 on: 03.08. 2018 13:56 »
No Doubt you and everyone else already knows of this chart outlining the normal stamping and gears etc.
https://mikesclassiccyclespares.com/bsagearchart/ But that is for the Swing Arm style box
The plunger/Rigid did not use these markings, as discussed in this earlier post
https://www.a7a10.net/forum/index.php?topic=6018.0
we have 5 plungers/rigids here all with a different markings on the "Sandwich" plate....

So whiles dad is away you get to scythe off and play on the computer eh.

And nice job on the new web page.
Bike Beesa
Trevor

Offline Peter in Aus

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Re: Gearbox ID
« Reply #11 on: 04.08. 2018 01:57 »
Thanks all for your input. It is quite apparent that the box in question is not as it came out of the factory, by a long shot.
It has the standard gears B 17 tooth D 23 tooth F 19 tooth and H 27 tooth. The gears are in good condition so will change the main shaft to a spline one and build it up for a spare box for the A7/10 plungers.
And thanks Mike for those links very helpful. *smile*
Peter   

Busselton West Australia
49 A7 longstroke
58 A10  SA