Looking back through this thread, I don't see any mention of the compression being tested. Maybe it's got low compression, and therefore seems weak when put under higher loads.
Indeed!
I didn't tested for compression because I assume it's perfect.
The bike doesn't use any oil whatsoever. No smoke, nothing.
Besides de carbon fouling on the plugs, they have no oil residues.
As of today I'm inclined to buy a whole new throttle assembly.
Yesterday, when I got back home from the test run I decided to disassemble everything in the throttle body.
As I removed it completely from the motorcycle, I found the intake plenum wet... Very wet.
I'm not 100% sure if it was gas, but I give it 90% of certainty, as my motorcycle only uses 2 fluids: gasoline and engine oil.
I am driving the motorcycle today and will see if that area gets wet again, so I can confirm if it is gas.
If it is, then, the injector is certainly the culprit of this madness.
There is no fuel regulator to suspect, as it has none. (Single fuel line to the injector)
I don't know about that, mainly because this issue started suddenly from one day to the other.