Hi, glad the info helped. I found another link that can be useful for things trump; http://www.britishcycle.com/help.htm
I hope you just took a wire from the battery to the coil(s)? Doesn't really matter but some components are sensitive to prolonged abuse - usually more modern electronic things rather than zener diodes whatever. The small spark could be indicative of a poor earth, low battery - as you're on electronic ignition there isn't much else. Sparks can look poor in certain light - if it runs it can't be too bad.
I'd be inclined to check even things that look ok (earth connections -dismantle, clean) and get the voltmeter/ammeter on others. The result of your test shows that there is a fault between either the battery and the ignition switch, with the switch itself or with something (a wire or connector) between switch and coil(s). If you don't have a volt meter, a working 12v bulb will help trace it by wiring it to the item you are testing and earth - with the ignition on.
Got mine running again at last - found several shorts around the points - and they weren't closing - and the distributor wasn't seating so the timing was slipping.
It still cut out and a quick natter with Oliver at TRisupply suggested petrol cap vent. A test run disproved this (and I got a face full of fuel when I revved it sans tank lid). Notably when it stutters to a halt there is a lack of compression. I think (and hope) I have simply gapped the rockers too tight. Everything crossed...
(why do we get an oriental holding our flag?