Bystarter system is a good part of what makes Honda cold starts effortless. See link below. If it's doing it when hot, there's still work to do on the Spree stalling issue. It's an interesting problem. Spree owners bring this up from time to time. Oddly no other Honda scooters I can recall in the same vintage have this issue.Mine does it cold or hot all the time.what's a bycollar?... L.o.l sorry I meant bystarter
The collar portion is an air control valve which when the bystarter valve is cold lets air bypass the throttle slide.
Bystarter explanation