BSA A65 Oil pressure.

[Old-Nail]

I mentioned before that I'm new to British bikes and my first impressions are quite worrying.

Firstly the oil pressure light in the headlamp of my 1970 A65 stays illuminated when riding, panic stricken I stopped and checked the oil return to the tank and that seemed ok, oil returning normally.
The switch is quite new so is perhaps unlikely to be faulty, should I be concerned?

The second thing is that the bike is (for me) a pig to start, there is a choke lever on the handlebars but no indication of which way is 'on' or 'off', presumably this being something you are just supposed to 'know'!

In one position the choke cable is slack, in the other position it is taught, can anyone tell me which of these is 'OFF'?

[georgecat]

Hi,

Not sure about your oil pressure light, it could be the pump or a faulty sender.

With regards to your choke, when the cable is taught the choke is on, you should only really need this when the engine is cold other than that it should start ok.

Regards,

Georgecat.

[L.A.B.]

Firstly the oil pressure light in the headlamp of my 1970 A65 stays illuminated when riding, panic stricken I stopped and checked the oil return to the tank and that seemed ok, oil returning normally.
The switch is quite new so is perhaps unlikely to be faulty, should I be concerned?

Yes I would be concerned as 'flow' and 'pressure' although related are different, as you could have flow but with little or no pressure if there is major engine wear or the pressure relief valve has stuck open?

The chances are it is the switch that is to blame (is it the correct type switch?) but it would be unwise not to check all eventualities as low (or no) oil pressure will wreck your engine in a very short time, the timing side main bearing plain bush may be badly worn if it is an original unmodified T/S type plain bearing?
I would suggest you test the pressure with a gauge as soon as possible?  

The second thing is that the bike is (for me) a pig to start, there is a choke lever on the handlebars but no indication of which way is 'on' or 'off', presumably this being something you are just supposed to 'know'!
In one position the choke cable is slack, in the other position it is taught, can anyone tell me which of these is 'OFF'?

Slack cable is choke 'ON' for Amal Mk 1 carbs which is generally the opposite way to modern carbs.

You may find it easier to leave the chokes off when starting? Just flood the carbs with the ticklers and kick.

[L.A.B.]

With regards to your choke, when the cable is taught the choke is on,

That is *not* correct for Amal Mk 1 carburettors

[georgecat]

Ta

[Old-Nail]

L.A.B. could you advise on the procedure for checking the oil pressure please as I think I must before I ride again.

Also what type of gauge do I need to buy?

[L.A.B.]

The normal A65 running oil pressure should be around 40-50 psi, and I think it may be prudent to seek some professional advice about this, maybe from someone like SRM? They will know how best to check it and what type of gauge and fittings are available to do so?
The pressure switch I believe should operate when the oil pressure drops below about 7 psi, so possibly replacing the switch would be the first course of action if the oil light doesn't go out at all, and this could turn out to be a simple switch problem as there is no guarantee it is an oil pressure problem at all so far, but nothing can really be ruled out at the moment?


 http://www.srm-engineering.com/workshop
SRM are likely to suggest changing the T/S bearing to their needle roller conversion, but that isn't always 100% necessary and it is quite expensive, as a decent T/S bush should last for thousands of miles, however many replacement plain T/S bushes available now are substandard quality.