I was thinking, I wonder if this would be worth it to try. Have the stock o2 sensor and wire up the sensor and the race mode cap on a switch so you can jump from closed loop to open loop with the flip of a switch for racing and fuel mileage ?
It would work but I think you would have one setting that runs great and one that is a stumbling mess.
I know of 2 issues... 1. You would have to shut off the bike between switching, ECU only checks for race plug only at start-up. 2. You would have to supply power to the O2 sensor heater circuit while is race mode to keep O2 sensor from getting damaged from exhaust contaminates. This can be done with a 2P2T switch. This is something I though of selling as a plug-in kit, but wasn't sure of the demand.
I have disagree with you on keeping the pre-heater on continuously, that would cause the most damage to the sensor. To quickly supply voltage to the ecm the sensor is preheated. Once the operating temp is reached the preheater circuit is turned off by the ecm. Now that is true for modern EFI auto systems, I would say the mikuni system would be same. As far as having switch to open and close the 02 circuit, I wouldn't want to add any more resistance to this circuit. You could bring the plug to a easy reach location, and unplug the o2, and install resistance plug when you wanted better fuel economy.
