jdaws
Active Member
I read that durring engine warm-up, the EFI runs in open-loop mode at a 12.0:1 air/fuel ratio. When the temp comes up it goes into closed-loop mode at a stoichiometric 14.7:1 AFR. In high-temp mode the idle drops to 950 RPM and the ECU goes to open-loop mode, richening the fuel mixture to 12.0:1 in an attempt to cool the engine. If you feather or blip the throttle the ECU retreats back to closed-loop mode at 14.7:1 which is too lean. If the bike accelerates past 1200 rpm at idle, the engine will stumble under high heat. This is why an EFI throttle should be left untouched during hot idle. This is for the closed-loop EFI (with O2 sensors) only.:s