Idle spec for these is 1100-1200 RPM. At 1400, the alternator is already beginning to produce a charge, which may explain the 13.1v reading you're getting. At a 1200 RPM idle (and headlight on), I usually see volts in the low 12's on mine.
I've never seen a setting spec list for the Canadian BS34s. I have no idea what clip slot on the needle was stock. I have compared one of those adjustable Canadian needles to a fixed clip U.S. model one though. The U.S. needle measures 50mm from the bottom tip to the fixed clip. The Canadian needle measures 50mm to it's top clip slot. That means any lower clip setting will be richer than the U.S. needle. The #2 (2nd from the top) slot may very well have been the stock setting for it.
Something else you can check is the air jet size in the bell housing where the air filter clamps on. That air jet feeds the idle circuit. U.S. models had a size 135. Most of the rest of the world with adjustable needle BS34s got a leaner size 130. But, being the air feed, less air means a richer mix.