Hello @invader and @salishversys!
I finally get filming the process of the "lengthy" startup!
After seeing the video a couple of times, finally I think I have an answer for the riddle of the subthrottle valves openings when I press the Start Button.
In short, I think I have to change the battery
Now, strtjx's Nerd corner:
The cause of this conclusion resides on the following claim:
I make a claim in which I explain why does my bike sometimes opens the subthrottle valves during the time in which I press the Starter Button on cold days. I believe that this happens because the battery is low on charge (due to cold and maybe age) as I will explain next.
It is well known that when the Starter Button is pressed, the Electric Starter drains a lot of electricity out from the battery. When the battery is low on charge, pressing the Starter Button turns the Electric Starter which drains a lot of energy out of the battery and decreases the voltage provided to the ECU and electric components of the Fuel Injection system.
The Electronic Fuel Injection (FI) system of the bike works over a predetermined voltage level provided by the battery. The voltage provided by the battery to the Electronic Fuel Injection (FI) system is reduced during the time the Electric Starter is rotating as a consequence of pressing the Starter Button.
My claim is that when the battery is at a certain low level and the Starter Button is pressed, the voltage supplied to the Electronic Fuel Injection system decreases to a level so low, that the Electronic FI system shuts itself off and also the Electric Starter stops rotating. During the time in which the Electronic FI system shuts itself off but the Starter Button is kept pressed, the battery regains strength up to a level acceptable for the Electronic FI system to power up again. It makes the Ignition sequence start one more time, namely, the servo valves check to their full open position and all the checking of the electronic components is performed by the ECU. Since the Starter Button is kept pressed, the Electric Starter start to rotate for the second time at the same time that the Ignition checking is performed.
Since the opening of the Main Throttle valve is performed by the Electronic FI system at the end of the checking cycle of the Subthrottle valves (I explain it on youtube's description of the previous video), the motorcycle engine starts running at its self-sustainable level only at the end of the check cycle of the Subthrottle valves. It explains why the Electric Starter can be heard doing a double cycle of rotations during the startup process, the Subthrottle valves open immediately during the pause of the two cycles of rotation of the Electric Starter and the fact that the motorcycle engine begins to run at its self-sustainable level only at the end of the Subthrottle valves check cycle.
That is the end of my plausible explanation. As I previously mentioned, this is just a claim. Better explanations are always welcome.
To be completely fair, the video was taken this afternoon and the bike was not very cold, since we were at around 7° C (45° F). This could explain the fact that actually the engine started to run at very low RPM's after the first cycle of the Electric Starter.
What do you guys think?