It's a weird setup, using a closed loop Lambda sensor capable ECU to run in open loop mode, w/o any feedback regarding AFR she's producing, but apparently the accuracy of the MAP sensor combinend with TPS and a lot of test runs enabled YAMAHA to create mappings/algorithms that produce a very stable carburator impersonation. Regarding hot start: That's exactly what I had to endure. Before taking the to me new bike onto one week of off road vacation to Italy, I "fine tuned" the CO setting some 5 notch towards rich, because I've read so on the net and wanted to improve hot start. That week was a dreadful torture. Bike would mostly start on third(!) button stab or first kick in neutral. I tried a lot of e-start procedures, including but not limited to rolling on the throttle, holding it open a tad like in TT600 times, blipping it etc.etc. Buddy on 450EXC would shook his head at my sorry e-start attempts on my then new bike, courteously not commenting on YAMAHA vs. e-start. Things became happy again only after returning home and playing with the FI diagnostic tool in the direction of what I then regarded as "crazily lean". Today I know better, and in hindsight find it amazing, that the bike back then did startup by button press at al. I'm just wondering how the bike accounts for elevation and adjusts accordingly in extreme changes without an O2 sensor.