side points 4CA Auto Advance Unit - maintenance

[hoogerbooger]

1965 Owners manual says every 500 miles:    Ensuring points stay uncontaminated: "smear the surface of the cam, very lightly with grease, or if this is not available, clean engine oil (SAE3-40) may be used. Lubricate the centrifugal timing control behind the unit with clean engine oil, paying particular attention to the pivots"

I found on-line a 1973-ish Lucas maintenance manual that incuded 4CA AAU's this just says( every 6000miles): "with the cam slot uppermost add one drop of engine oil to the slot . Place one drop of oil on each contact breaker pivot post and smear the surface of the cam very lightly with Mobilgrease No2 or equivalent"

( My cam doesn't have a slot, but unlike the owners manual this is specifically saying oil the cam spindle.)

RR says some AAU unit spindles were factory lubricated with graphite which should not be mixed with oil, but suggests that these will now be long perished in function and it is best to strip the unit clean and from thereon use oil.

From the above I deduce:

1) greasing the cam is preferred over oiling.
2) That for the above a NLGI 2 high temperature LM multi purpose grease will be ok

What I am not sure about are:

3) To dismantle the unit to clean all parts including the spindle, is it just a case of undoing the springs and pulling. I believe the cam is a push fit on.....but I am not sure how robust the push fit is and if dismantling can cause wear/problems with the push fit & future function?

4) I read online on B50.0rg and elsewhere comments on the bob-weight grooves/guides wearing and causing problems with movement and people then 'lanishing' the groooves/guides to refurbish. Is a light coating of oil every 5000 miles enough to minimise further wear?  I was wondering whether a lighter high temperature semi fluid grease may still allow free movement of the bobweights, but be more likely to last the service interval ?

Advice welcome

[Blackthou]

I haven't played with the points on a BSA single the way you describe as fairly new to single ownership but have done similar on a Triumph twin. On the Triumph the cam was on a taper. You removed the centre screw fitted one similar but longer and jacked it off. The points, backplate etc would come off as an assembly. If you flipped it over you coud access the weights etc for lube.

I'd imagine there would be wear on both male and female parts so they're hardly likely to seize. I'm sure a smear of copperslip would be fine, some greases can dry and harden. You can flick the cam and watch the weights move and return. The springs in reality should be more of a concern as with age they lose their temper and are less effective but to be honest as the bike isn't high revving it probably wouldn't be noticeable.

Yes it's great and satifying to do the maintenence as per book but IMO having done that before I would get a can of WD40 and with the long tube inserted in the nozzle, bend it behind the backplate, either end and have a couple of squirts.

The cam on a Triumph also has a felt pad, opposite the heel of the points, which you lubricate occasionally and makes more sense.

Might not be a lot of use to you but thought I'd say in case.