Until the engine reaches a pre defined operating temperature and the 02 sensor is up to a working temp your bike is in open loop.
In open loop it uses all the other sensors to reference against the map tables in order to try and maintain a 14.6:1 air/ fuel ratio when idling, gentle acceleration or cruising.
Without the O2 sensor in use it has no way of checking that this has been achieved.
Once the engine temp is around 25 degs C and the O2 sensor is up to temp your bike enters in to closed loop.
In closed loop the O2 sensor is been used as well. Now the bike can monitor the emissions and now knows if the air fuel ratio is correct and will make small adjustments many times a second to maintain 14.6:1 A/F .
Your bike will only remain in "true" closed loop when idling, gentle acceleration and cruising.
At any other time a different fuel/air ratio is required. There are a number of "overrides" that can come in to play when this occurs to give a richer or leaner mixture.
I didn't know that a lean mixture gives high HC's , that doesn't make sense to me but I have no knowledge about this
here is a graph of my RX3 showing a zero injector pulse when the throttle position hits zero
And the next graph is of my engine temp before I changed the thermostat. the temp only peeks at the end because I came to a stop and let it idle. (temp in degs C )
Attachment 8236
Attachment 8237