The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: kabadi GF 1961 on 26.11. 2015 18:18

Title: Alternator Primary questions and help needed
Post by: kabadi GF 1961 on 26.11. 2015 18:18
Hello All
Happy thanksgiving !!
 
I have a alternator primary case set,
 I want to know where I can find the three studs and bolts for mounting the alternator?
 Where can I source the flat cover plate that goes on the outer cover?
 what was the original lucas Alternator number?
and more question to come later. I have a crankshaft with extension being made for this set up.
Cheers
Title: Re: Alternator Primary questions and help needed
Post by: kabadi GF 1961 on 26.11. 2015 18:19
more pictures attached
thx
Title: Re: Alternator Primary questions and help needed
Post by: Rocket Racer on 27.11. 2015 08:23
I'd suspect this is like the C12 set up, there is an alloy basket that supports the alternator and bolts to the inner case. I don't believe I have a spare but can photograph if that helps
Title: Re: Alternator Primary questions and help needed
Post by: kabadi GF 1961 on 27.11. 2015 12:49
Yes
If you have a picture , it can help
Thank you
Title: Re: Alternator Primary questions and help needed
Post by: edboy on 27.11. 2015 19:37
if i may be so bold and suggest the design was lifted from the alt. triumph speed twin. i m sure the triumph studs will fit and the stator fits the outer cover not a housing like norton, late bsa. the missing cover is a plain affair and i would just mill a bit of ally to fit with 3 screw holes. i have the cases but no crank to match but  if one is propping up your billybong in the outback i would be interested.
Title: Re: Alternator Primary questions and help needed
Post by: WozzA on 27.11. 2015 20:55
I've never seen one in the flesh, but to me It looks like the 3 cover screws & nuts hold it all together..
Title: Re: Alternator Primary questions and help needed
Post by: trevinoz on 27.11. 2015 22:34
No Wozza, there are 6 holes, 3 for studs & 3 for cover screws.
Title: Re: Alternator Primary questions and help needed
Post by: WozzA on 27.11. 2015 22:51
Should have known I'd bugger it up...   *shh*   *whistle*
Title: Re: Alternator Primary questions and help needed
Post by: BSA_54A10 on 18.12. 2015 11:15
And because he rotor is bolted to the crank and the stator is bolted to the out chain case hey are a bitch to set up with even spacing
Title: Re: Alternator Primary questions and help needed
Post by: Blackcat on 30.12. 2015 20:24
Hi!

You will need the following special bolts for your A10/A7 alternator chain case. I found out the hard way that there is nothing available in the BSA emporium and no NOS. It’s trial and error. I assembled the chain cases and the crankcases using the following:

a. One 5/16 inch screw with ¾ of an inch of whitworth thread. This needs ten thou taken off the diameter of the screw head to fit into the outer alternator cover. This goes from the outer cover right into the crankcase.
b. Two ¼ inch screws with ¾ of an inch of whitworth thread to fit into the outer alternator cover. These go from the outer cover right into thr crankcase.
c. Two 5/16 inch screw with ¾ of an inch of whitworth thread which secure the inner chain case to the crankcase.
d. Twelve ¼ inch screws, ½ inch long, completely threaded with whitworth thread which secure the outer to the inner chain covers. 

The late B31/33 single alternator chain cases are completely different and require major surgery to fit to the pre-unit twins.  They have virtually no parts in common with the A7/A10 alternator chaincases

Hope this is useful.

Martin


Title: Re: Alternator Primary questions and help needed
Post by: Blackcat on 30.12. 2015 20:52
Hi again!

The short answer is you can’t buy a cover, there is more chance of finding Excalibur! I checked with a friendly Triumph spares man. The Triumph Speed twin cover is different. The BSA covers aren’t very nice anyway as I have a damaged one. Ugly chromed stamping which looks like the hurried bodge it probably was. As noted in an earlier reply I made up an alloy disc which at least looks like it might belong!

The alternator was a Lucas 19-1222 un-encapsulated type but with some hacking of the encapsulation anything Lucas from the 1960s could be made to fit.

When Brian owned Lightning Spares he had part 67-1395 Alternator Stator Fixing Stud [3 off] available.

Anyone know the sizes of the three Alternator Distance Pieces [42-7540]? I think they are 1/4 inch internal diameter with 1/2 inch external diameter and approx 1/2 thick but it needs the thickness checking to see they don’t foul the encapsulation and fit the stator at right position relative to the rotor. Probably could be made up from spacers from another alternator fitted BSA/Triumph?

Regards

Martin
Title: Re: Alternator Primary questions and help needed
Post by: edboy on 01.01. 2016 20:59
adjusting the stator is easy if you think about it blackcat. make up some spacers from card or ally and space rotor evenly then offer the whole lot attached to the outer primary cover to the engine  crankshaft. with the outer cover off it will be easy to see where to adjust the stator. you could also make a few studs up to slide the primary case on for alignment and ease.