Author Topic: A10 Plunger Primary  (Read 506 times)

Online manxman

  • A's Best Friend
  • ***
  • Join Date: Jul 2017
  • Posts: 58
  • Karma: 1
A10 Plunger Primary
« on: 14.11. 2017 17:49 »
Being a novice in BSA Plunger motors I was under the assumption that the primary chain, clutch, and motor sprocket were duplex.  When I opened the primary on my newly acquired 1953 A10 motor I was surprised to find a triplex chain, clutch, and sprocket! Any answers?

Offline Rex

  • Resident Legend
  • *****
  • Join Date: Apr 2017
  • Posts: 639
  • Karma: 2
Re: A10 Plunger Primary
« Reply #1 on: 14.11. 2017 18:37 »
I found the same and was also surprised at the level of sophistication in an engine this old. Rather different to the expected single-row primary chain.
Errr...so what was the question again... *conf*

Online manxman

  • A's Best Friend
  • ***
  • Join Date: Jul 2017
  • Posts: 58
  • Karma: 1
Re: A10 Plunger Primary
« Reply #2 on: 14.11. 2017 18:43 »
I wondered if the triplex was standard across the range or what year the change was made?

Offline a10gf

  • Wise & Enlightened
  • *
  • Join Date: Sep 2006
  • Posts: 2845
  • Karma: 43
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: A10 Plunger Primary
« Reply #3 on: 14.11. 2017 18:43 »
Twin chain on my plunger...

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8503
  • Karma: 112
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: A10 Plunger Primary
« Reply #4 on: 14.11. 2017 19:02 »
Triplex was introduced in the A50/65, so someone has done a conversion.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online JulianS

  • 1962 A10
  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1075
  • Karma: 20
Re: A10 Plunger Primary
« Reply #5 on: 14.11. 2017 19:11 »
The 1954 data book shows the A10 Super Flash was fitted with a triplex primary chain, and was available on other plunger twins and A10 to special order.

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8503
  • Karma: 112
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: A10 Plunger Primary
« Reply #6 on: 14.11. 2017 19:20 »
Well there you go. A day doesn't go by that I don't learn something.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online manxman

  • A's Best Friend
  • ***
  • Join Date: Jul 2017
  • Posts: 58
  • Karma: 1
Re: A10 Plunger Primary
« Reply #7 on: 14.11. 2017 20:05 »
Mine is definatelt a plunger clutch complete with top hat, not a A65. Must have the optional primary drive. Mine is not a Superflash, unfortunately. Numbers are BA10.....with HC beneath.

Online trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 2933
  • Karma: 67
Re: A10 Plunger Primary
« Reply #8 on: 14.11. 2017 20:21 »
It seems to have been an American market thing, I read somewhere many years ago that the Yanks were destroying the duplex drives so a triplex was made available.
I also have found one on a BA10/HC set of cases which were brought here from the U.S.