A10 police Alternator inner primary cover wanted!! Help!!

[BSARoadRocket]

I'm looking for an inner primary cover to match an Alternator model outer primary cover from a police model A10.  I found most of the screw holes of the standard A10 inner primary cover line up with an Alternator model primary cover but...the gasket surface does not match up as the Alternator primary cover is a different casting.

Any help, leads, and suggestions would be appreciated!!! 

[Briz]

Good luck.
There are a lot more outer covers around than inners, because the single cylinder alternator models used the same outer cover but a different inner.

[Beezageezauk]

Heyup Briz,

The alternator model B31 and B33 used a different inner and outer primary chaincase to the alternator A10.  On the B series the alternator attaches to the inner chaincase and on the A series it attaches to the outer cover.

However, I don't know if a matched pair of B31/B33 alternator chaincases would fit onto the A10 alternator model. 

BSARoadRocket....I think that it would be easier to source the B31/B33 type.  These are becoming quite scarce now but check that they would fit first if you choose to go down this route.  Good luck from me and keep us posted as to how you get on with it.

Beezageezauk.

[chaterlea25]

HI,
Good luck with the search !!
Did you see what these cases and alternator crank made on fleabay the other day

http://www.ebay.co.uk/itm/261319764655?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

http://www.ebay.co.uk/itm/261319757916?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649


John

[BSARoadRocket]

I saw...anybody who would pay that price for a crank is completely out to lunch.  Anybody with access to a lathe and some basic machining skills can easily modify a common crank to alternator specs.  I bought my outer on ebay and while it's not much use with out an inner, it did not cost me much and if it comes down to it I can modify a standard inner to match my outer.

The screw holes all line up between alternator and generator covers so I suspect that there could be a few ex-police model A10's running around with alternator inner covers and standard generator model outer covers.  I'm hoping something like this will somehow come out of the woodwork. 

The B31/B33 alternator model covers are quite different and will not match up to the twin crank case with out serious modifications but they may still be an option.

[Briz]

Heyup Briz,

The alternator model B31 and B33 used a different inner and outer primary chaincase to the alternator A10.  On the B series the alternator attaches to the inner chaincase and on the A series it attaches to the outer cover.

Ah! didn't realise that. Thanks. I once bought some B31 cases and was going to modify them to fit the twin. Never got round to it. The hole would need boring out quite a bit, and mine had already been attacked with a file so hard to centre up on.

Holy crap! just looked at those ebay links. I think I'd rather carve an inner out of solid than pay £440 for a set of chaincases.

[Stephen Foster]

Would it be possible to build up a standard set by T.I.G welding then mill , drill & tap holes in the correct situation ?
The obvious snag would be requiring a template ?

[BSARoadRocket]

The ironic thing is that all of the 1/4x20 screw holes are in the same place on the alternator covers as the generator covers so I can actually screw my alternator outer cover to a generator inner cover and all the screw holes line up.  The problem is that the gasket surfaces don't line up and there are actually gaps you can see through because the gasket surfaces are on a different level.  I could cure the problem by just making a spacer out of say 1/8 aluminum plate and placing it between the covers but it  would look like an after thought.

The motor/alternator end of the chain case has a slightly larger diameter by about  1/4 inch. The top and bottom of the chain case tapers outward a little to match the larger diameter and this is my problem.  I believe that a skilled welder could actually build up a standard generator inner cover with weld and then I could surface it and file it down to match the alternator outer cover.  There would likely be some warping but this is probably going to be my only option to get an alternator inner cover.

As far as converting a RGS to an alternator.....you might want to look into some reproductions of the B33 alternator covers as I believe they are available from ABSAF.  You would have to modify them to fit the A10 engine but the outer cover actually looks better than the A10 version as it does not have the chromed steel stamped inspection plate that goes over the stator.   If you are only running a headlight and one tail light I'm not sure the expense would be worth it and the alternator would really bugger up the looks of an RGS...in my opinion.

Personally I always thought the generator model primary covers looked ugly, but I'm interested in putting one on my bike as a practical thing so I can run extra lights and possibly an electronic ignition and have more reliability.   I tried an Alton alternator when they first came out and had way too many problems  with belt v belt slippage as the Alton was very stiff and hard to turn.  For now I'm going to go back to a 6V dynamo with a modern regulator and one of SRMs toothed belt drive kits and see how that works. 


Part of my motivation to run an alternator is because I would like to run a newly manufactured easy to get alternator of the same type that is run on A65s and unit Triumphs but I have not done enough homework yet to know if the common alternator will even fit into the A10 police type primary cover. 

[Stephen Foster]

Do You think You could post a sketch indicating the areas which would need building up with weld please ?
I could possibly suggest ways to minimise warping , etc if so .
I am a little confused as I have never seen a generator type inner to compare .

Best Wishes,
Steve ..

[WozzA]

I've only ever seen one in a video...  on this NorBSA
http://www.youtube.com/watch?v=e3Xyt15_UYE

[chaterlea25]

Hi, All
One here on Steve McFarlanes site

http://www.startyourbsa.com/

HTH
John

[muskrat]

That cover looks like the one on a mates ABSAF Goldy with alternator.
He dropped it two weeks ago and the footpeg said hello to the clutch.
Cheers