Bought a Powerspark ignition unit from SimonBBC, and trying to fit it now, and for the life of me I can't fit the rotor arm which came with the kit. Either of them - there's a black weird shaped one which I am supposed to fit but also a black magnetic ring and red arm which is for aftermarket dizzys apparently. Neither the black weird shaped one or the black ring will go over the spindle.
I'd rather use the black ring + red rotor arm to be honest as it seems less weird, but no good when neither will fit.
Anyone know what I'm doing wrong? It's really annoying me!

This is the one I've bought: http://www.simonbbc....kit?cPath=2_19