Author Topic: Was there an A10 long stroke engine  (Read 322 times)

Offline barry2

  • Moving Up
  • **
  • Join Date: Aug 2018
  • Posts: 31
  • Karma: 0
Was there an A10 long stroke engine
« on: 07.02. 2019 00:51 »
Hi mates
Was there a long stroke BSA A10 engine? and/or was there a close coupled A10? thanks a lot
Barry
WA

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 7814
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Was there an A10 long stroke engine
« Reply #1 on: 07.02. 2019 01:38 »
G'day Barry.
Not from the factory that I know of.
If you put an A10 crank into an A65 = a long stroke A65 = 742cc.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline barry2

  • Moving Up
  • **
  • Join Date: Aug 2018
  • Posts: 31
  • Karma: 0
Re: Was there an A10 long stroke engine
« Reply #2 on: 07.02. 2019 01:48 »
Hi Mates
I was refering to early engines ie a close coupled A10 that looked a long stroke A7
Barry
WA

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 7814
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Was there an A10 long stroke engine
« Reply #3 on: 07.02. 2019 06:05 »
G'day Barry.
The only "long stroke" was the early A7 500 with a stroke of 82mm from 47 to 50. Then the AA7 had a shorter stroke of 72.6mm. The A10 started in 50 (semi unit till 56, S/a started in 54) and had a stroke of 84mm till the end in 63. No "long stroke" A10 for public sales but you never know what lurked in the race department.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline barry2

  • Moving Up
  • **
  • Join Date: Aug 2018
  • Posts: 31
  • Karma: 0
Re: Was there an A10 long stroke engine
« Reply #4 on: 07.02. 2019 07:35 »
Hi Mates
Thanks for that, was thinking, the short A7 and A10 had the same engine/crank but w/ diff bore
and all the close coupled had same crank w/ diff bore
Barry
WA

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 7814
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Was there an A10 long stroke engine
« Reply #5 on: 07.02. 2019 08:07 »
The A50 and A65 share the same stroke of 74mm. A50 bore is 65.5mm, A65 bore is 75mm.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Swarfcut

  • Resident Legend
  • *****
  • Join Date: Oct 2018
  • Posts: 598
  • Karma: 8
Re: Was there an A10 long stroke engine
« Reply #6 on: 07.02. 2019 09:08 »
 Anyone tried an A7 crank, small journal A10 rods and pistons in a cut down A10 barrel......if only to avoid the expense of repairing those missing  top fins? Would give a capacity of just under 600cc and give an almost over square stroke/bore ratio. Plus more torque than a standard A7 (bigger piston crown surface area).

   Barry.... There is a picture of a twin engined bike, a homebrew special, in Roy Bacon's "BSA Twins and Triples"...Comes in Chapter 10......"Oddments."

 Swarfy.

 

Online Klaus

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 343
  • Karma: 9
Re: Was there an A10 long stroke engine
« Reply #7 on: 07.02. 2019 09:28 »
Hy Swarfi,

I do the other way, A65 crank and 6" rod in A7 case and a shortend thickflange A10 barrel whos missing their top fin. Pistons are JP 0894 STD with 72 bore.

cheers Klaus


If you think, everything is under control, you are not fast enought.

Offline Swarfcut

  • Resident Legend
  • *****
  • Join Date: Oct 2018
  • Posts: 598
  • Karma: 8
Re: Was there an A10 long stroke engine
« Reply #8 on: 07.02. 2019 09:40 »
Klaus  That is very clever. A big journal crank, better rods with a nice big piston pin. Short stroke/ bigger bore. Looks just like a standard A7.  A wolf in sheep's clothing.  NICE.

 Swarfy.

Online Klaus

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 343
  • Karma: 9
Re: Was there an A10 long stroke engine
« Reply #9 on: 07.02. 2019 13:44 »
Yes, thats the plan in combination with a megacycle race cam and a twincarbhead, I will devil the big bikes up to 1000cc at the racetrack.

But it is a lot of work, and will never do again. I had the parts, the damaged barrel, a cheap a65 crank, and the cases. The hadest thing was sort it out the pistons. The SRM rods have no bush, so I only can fit a 3/4 inch pin.

cheers Klaus


If you think, everything is under control, you are not fast enought.