Having never even got my strobe out of the drawer for well over 20 years I was curious about this.
So I just tried it on the Monster and yes it does flash.
The little widget that goes between spark plug and cap was a ropey fit and was clearly meant to fit with the nipple on the plug, which mine doesn't have, so it fell out after a few seconds but did flash whilst connected.
I bought it from a shop (remember those?) in the 80's and all it says is that there were two models available 12V and 240V. Mine is the mains version.
All I can suggest is that the connection between spark plug and cap needs looking at, even if that means making up something that will guarantee a connection.
Probably not that much help to you as mine is an ie model so perhaps not a direct comparison to yours?
