Rotation is easy to tell, hold the taper and twist the point cam. Whichever direction causes the bob-weights to move outward is the direction of rotation. Look in the back, thee usually is a degree marking. That number is not listed for the triple or the '71 A65.
Well 12 deg on the cam is 24 deg BTC and that is not ringing any bells for me. The aa units were common to every British bike so it could be virtually from any thing post 1959 ( which is about when they started using that unit me thinks)
Thanks ALL Alex, i have noticed in other posts you have an amazing amount of information. thanks for your reply. I have searched the net, brit parts houses, etc and can not find reference to that number. I have a NOS one available to me to purchase. I was hoping it would fit my 6ca BSA lightning, and i guess it will. thanks
Joined: Sep 2002 Posts: 7,812Alex
BritBike Forum member
BritBike Forum member
Joined: Sep 2002
MAP and BO price list show it as being a replacement for 54419653, really intended for unit singles. I don't know what the difference is between that and a twin AAU unit. They look identical to me, have the same amount of advance, so maybe the springs are different? bob weight mass? I dunno but it seems like it should work fine. Supplier parts catalogs and price lists and can be very useful in this respect.
A smattering: '53 Gold Flash '67 Royal Star '71 Rickman Metisse '40 Silver Star '37 Rudge Special sixtyseventy Lightboltrocket road racer...and many more.
I have a stack of unit single aa units and a couple of now redundant A 65 ones and I can see no difference in the cam profiles between the B 50 , B 44 & the A 65 ones. When pulled apart the only difference that I could see was the springs and the hole in the plate to control the advance. I even have a couple of plates with 2 different holes, stamped with 2 different advance numbers
Nert, I don't recall you mentioning what bike you are fitting. I was never opposed to points. In fact my singles have points and the twin electronic. I have interchanged AA's from different bikes and the seem to work just fine. Everything was either points or magneto when I grew up so fiddling with points was never an issue. I decided to go ahead and fit my 66 A65 with a Boyer as timing the earlier bikes with the 4ca pints was very ticklish. I can tell you that the Boyer also provided a more gentle advance that largely cured pinking. I have't had the points cover off in years on the a65 so there is something to be said for the Boyers. Your timing never changes whereas with points it does change as the rublock wears or the points deteriorate thru arcing. But is is a personal choice. The big advantage with points is that you can carry cheap spares in the event you do have a problem out on the road Bnd you can run a long way off a battery if you have charging system problems. I once made it home on battery voltage of about 6-7 volts when a wire from my alternator broke. When you drop below about 10 volts with a Boyer it quits sparking. This site has guys that are strictly electronic and others that prefer points. I guess I am somewhere in between. Also setting points within a few thousandths with trifocals down on your knees is another reason to support Boyer, but it's a personal choice.
MR Mike I have a 66' lightning. I picked up a used 6ca aau and points plate of e-bay. As it is worn and i am in the middle of a rebuild, i wanted to find a new old stock unit to put in. BSA_WM20 Its amazing how we all collect these little "bitsa" parts. Can't throw any thing out. It has to be better than some other one, and gee it has to have value. Ive waste a lot of time and money replacing a part to one a little better than what i have. Than another one, a little bit better comes along. Before ya know it, ya got a collection. So, now i am looking for NOS.