The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Flatboy 1950 on 16.10. 2010 18:01

Title: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 16.10. 2010 18:01
Hi Chaps , I have a set of the later A10 Alternator pri. cases with a chromed round cover over the alt.
My question is : Are all the inner pri. mountings the same ?? Will these alt. cases fit a "gen" motor ??
Since the windings mount on the outer case , there is no reason to have changed the mountings of the inner case. (??)
Or is there a special left crankcase for the alternator inner primary to mount to ??

Flatboy1950
Title: Re: BSA A10 Alternator primary chain cases.
Post by: muskrat on 16.10. 2010 20:53
G'day Fatboy 1950, Welcome to the forum.
                                                                   A rare item you have there, mostly used on police models. I remember reading somewhere that the inner cover is different but would bolt to the cases as normal.
 A friend down here has a ABSAF Goldie that came with an alternator and said the covers would fit my A10. Just waiting for him to go on holidays so I can nic'em.
                 Cheers
Title: Re: BSA A10 Alternator primary chain cases.
Post by: trevinoz on 16.10. 2010 22:46
Flatboy,
               I suppose the cases will fit but to fit an alternator to a generator engine you will need the alternator crankshaft.
Trev.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 17.10. 2010 07:35
Hi Chaps , A lad whose cases have been ruined by an "expert welder" wants to use these on his gen. equipped A10 to get it back on the road , no intention of installing an alternator.
Hence the question : Will they fit ??
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 17.10. 2010 10:48
Here are pix of the BSA primary chaincase.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 17.10. 2010 12:42
Hi Chaps , Well I looked at the pics of the A10 on the dyno , with the outer primary off & to me it looks as though the mounting of the inner is exactly the same as the inner " Alternator " case ....
Thanks , Flatboy 1950
Title: Re: BSA A10 Alternator primary chain cases.
Post by: bsa-bill on 10.06. 2011 17:34
I'm on shaky ground here but I think the Goldie cases have different holes for attatching to the crankcase and possible the large hole at the front is maybe larger on a Goldie, I'll be happy to be put straight though - knowledge is power
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 10.06. 2011 18:25
Hi , I am in South Africa & the postage from here normally kills any deal !!
The Post Office here also will not insure any items posted to the UK & continent !!
I don't need std. cases , my brother had 3 s/a A10's & 2 plunger A10's years ago , but they are all long gone.
I doubt if I will ever use them , so they can go but local sales are so much easier.

Regards , Flatboy.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Bill18 on 06.07. 2012 10:05
Hi Flatboy,
I have the same primary chain case as you on my A10 - with the removable circular cover over the crank shaft end spring. I have never seen another one like mine until I came across your photo in the forum just now. Do you know anything about why they are different from the "usual" one that has a dome instead of the removable circular cover?
Bill
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Brian on 06.07. 2012 10:26
The parts book lists different numbers for the inner covers but that doesnt mean they are not interchangeable. You would have to offer them up to the bike and see.

All the ones I have seen on A10's have had the removeable chrome cover, the B series have a one piece moulded cover.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: BSA_54A10 on 06.07. 2012 11:54
Some police A 10's had both generators & alternators.
The geny was connected to the bike as per normal
The alternator was on a separate circuit with the 12 V battery, radio & flashing light,
So it should fit.

As the others have said the alternator covers are as rare as rocking horse poo.
Should be able to find lots og blokes willing to swap you two standards for that one.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: fido on 06.07. 2012 14:07
What a confusing thread!  *conf* I take it the references to generators actually mean dynamos? I tend to think of the flywheel magnetos with separate coils for lights etc. (used on stuff like Villiers 2 strokes) as generators, otherwise you have a dynamo or an alternator.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: iansoady on 06.07. 2012 14:34
What a confusing thread!  *conf* I take it the references to generators actually mean dynamos? I tend to think of the flywheel magnetos with separate coils for lights etc. (used on stuff like Villiers 2 strokes) as generators, otherwise you have a dynamo or an alternator.

Indeed.

However I believe our transatlantic cousins call dynamos generators. It is confusing as both dynamos and alternators are in fact generators.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: Flatboy 1950 on 06.07. 2012 16:54
Around here , dynamo is that little thing on a bicycle that is friction driven to light the cycle lamp.
DC comes from Generator.
AC from Alternator.

Cheer , Flarboy.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: muskrat on 06.07. 2012 19:58
You say tomaytoe I say tomartoe. I've always called them generators. Saying dynamo to most non-pommie bike riders is met with a wtf is that.
Cheers
Title: Re: BSA A10 Alternator primary chain cases.
Post by: iansoady on 07.07. 2012 10:59
Yebbut they were made by Lucas and that's what they called them. They should (have) know(n)..........
Title: Re: BSA A10 Alternator primary chain cases.
Post by: duTch on 07.07. 2012 11:09
My first thought was the dynamo on the treadly-cycle, but are they actually AC or DC as the light used to flicker a lot?

 Love to hear that 'Dynamo Hum'
 cheers
 
Title: Re: BSA A10 Alternator primary chain cases.
Post by: bsa-bill on 07.07. 2012 11:30
DC I think Dutch
As for the flicker do you have one leg a bit shorter than the other perchance  *whistle*
I don't think there was any sort of voltage control so being young and fit in those days I used to be forever blowing tail light bulbs, I also recall some posh types that had a battery (accumulator type ?) in circuit.
I still have a Miller one in the shed, back up system for the A --- no I'm getting silly
Title: Re: BSA A10 Alternator primary chain cases.
Post by: bonny on 07.07. 2012 21:27
Surely the cases are only one part of the equation ? what do you do with the crank cush drive if the rotor is on the end of the crank ? there must have been a triumph clutch fitted as standard to bikes fitted with an alternator.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: duTch on 07.07. 2012 22:25
Back in the '70s I came across an alternator crank, intended to use, but as you suggest Bonny, and due to lack of information->too hard basket, I ended up swapping it for something I could use . In retrospect it may well have been a A65 one anyway tho'. It all seems to be lost or well guarded information for 'need-to-know' basis.
  Bill- maybe the legs just couldn't go fast enough!
 Cheers duTch
Title: Re: BSA A10 Alternator primary chain cases.
Post by: trevinoz on 07.07. 2012 22:46
The alternator is connected to the same circuit as the generator/dynamo via the rectifier and the lighting switch.
The lighting switch cuts in the full alternator when the lights are switched on with only part of it working at other times.
This is the same system used on other makes as a crude form of voltage control.
Thus the two systems run in parallel and is a 6 volt system, not a 6V and separate 12V on the same machine.
Attached are the relevant pages of service sheet 813A.
The first time I saw an alternator equipped A10 was about 1969 in a local dealer's workshop.
I am pretty sure that it had the 1 piece chaincase cover as have B33s that I have seen.
However, all other A chaincase covers I have seen were 2 piece.
The alternator was also available for the A7, there was one locally a few years ago.

Trev.
Title: Re: BSA A10 Alternator primary chain cases.
Post by: chaterlea25 on 08.07. 2012 15:16
Hi All,
Theres an A10 bottom end on fleabay that has an alternator rotor on the crank end!!!
I dont know if this is even a BSA crank or not fitted???? seems as if the flywheel is removed or radically lightened???
number 330759188351
Nowt to do with me as usual *ex*

John O R
Title: Re: BSA A10 Alternator primary chain cases.
Post by: duTch on 09.07. 2012 12:42
Thanks Trev,
                  Will have a better look after, but the bit that I do suddenly understand, is, why it's 'a closely guarded secret!'!
 Sounds like maybe a primitive kind of relay??

   Had a look at that John, and I say yup, the flywheel is removed, but looks like maybe(?) one of the ones with 6 side bolts as no bolt-hole above the journal where one holds the sludge trap, a bit odd tho'...?