Problem with re-commissioned KZ1300

I'm putting a 1980 KZ1300 back on the road in Hong Kong after buying it in South Africa. It was "renovated" in SA before I bought it, but I realise it was more of a cosmetic tart-up. The wiring especially is a bit of a botch up. Anyway, It starts well, runs pretty well but has this problem:

After a few minutes riding, it just cuts out. Instant - no coughing or the like, just cuts out.
Pull over, switch off and back on and it starts up fine.
Ride another few minutes and it cuts out again. Same again - it'll start after switching off and back on.
One thing I note is the oil pressure light is always on - I think that's just an electrical issue rather than a lack of pressure - haven't got a new switch yet.

Any ideas on what this problem could be? Is there a safety cut-out after a few minutes if the bike thinks there's no oil pressure? Could it be a dodgy ignition switch?

Any thoughts are greatly appreciated.

Keith

cutting out dead sounds like an electrical problem. Your oil light "might" be the oil level sensor which is reported to be a bit temperamental. Just what I have heard though as mine does not have an oil level sensor.

Definitely sounds like an electrical issue. The 80 did not have a oil-level warning light. If this is the case then a P.O. has installed a later year oil-pan. Regarding the Oil-Light remaining ON: An oil pressure gauge installed in place of or "Tee"'d " off the Oil Pressure switch will sort-out this concern. There is no "Safety Cut-Out" system.
A "Dodgy" ignition switch could be the problem but I'd suggest a progressive electrical diagnosis starting with the battery. You're going to need a wiring schematic so if you don't have a Manual - get one. There's a PDF file for a Manual available on this site but a Hard-Copy is invaluable !!!
First thing to look for is a faulty 30amp MAIN fuse. Remove the fuse holder, clean the fuse clips with "ScotchBrite" and check the connections on the bottom of the fuse holder. Solder them if they haven't been already. Replace the fuse ! If the problem persists then check the Ballast-resistor YELLOW power IN connection. Corrosion here can interrupt power to all three PINK leads feeding the ign.-coils. Failing this, move to the plugs on the IGNITOR. We're primarily concerned about the plug that carries the power for the igniter but clean the TRIGGER wires plug too!
You should get a sense of where this is going. Start with the simple stuff. With the manuals diagnostics, a schematic and a meter you will find the problem and I suspect it will be a simple fix. One corroded terminal in the primary ignition wiring will produce the problem you have. I had an identical issue this summer and it turned out to be a poor main-fuse connection. Heat generated from high resistance connection can shut-down everything!

Just an alternative theory - your problem does sound electrical - but could be a fuel problem. Try riding a bit with your fuel cap open - that will let you know if your tank is venting properly. Next thing I'd try is bypass the electric fuel valve.

Always good to consider everything but I don't think it's fuel related. I've had a blocked tank-vent. As with most fuel starvation issues the engine would start to miss and stumble - not cut out and go dead immediately,

Better late than never... An update that may help others in the future. The problem was completely fixed when I put a new igniter unit from Carmo. It was an easy fit - just unplug and plug in the new one - and the bike is now AWESOME!!

Many thanks again for all the suggestions.