Was that the same motor as used in the blue "Inavlid" cars many years ago, they were Villiers 210cc if memort serves.

Only bike I ever had with a decomp was a Bullet 500, came in handy for getting it over TDC before giving it the big kick.

Once you got used to the ammeter "twitch" for want of a better word it would more often than not fire up first kick.