Sometimes simply clutching in and letting the bike attempt to return to idle when coming to a stop kills the engine.
Interesting.
What i mean to say is, something like that, to me, smacks of a faulty idle control servo, or possibly a faulty position feedback from it(?). And since we are all only 'discussing and hypothesizing' about it, I mean, why not?
Example of why I say that:
I don't know if you guys ever noticed this... but a Duke ETC doesn't work exactly like, say, an automotive Electronic Throttle Body. Case in point, an automotive ETC 'rests' in a partially open position, with no power applied; closing it completely requires electrical power that works directly against a high tension spring. When the key is turned on, the ECU 'closes' the ETC momentarily, in order to reestablish the minimum airflow/minimum authority throttle body position. But unless the ECU 'commands' maximum engine braking, releasing power from the throttle body simply leaves it in a rest open position. The act of 'reducing' idle rpm, in this case, comes from the application of pulse-width modulated reverse current; if it doesn't close when commanded, the system will be disabled entirely and a code will set... but it can't just close on its own.
Right, right, right...
But pull out the air filter lid of a 2017+ Duke 390, and you will see something 'different' when you turn the key on.
Turning the key on results in the ECU powering up, moments later the ETC 'opens' to a startup position.
And if you turn the key off, then watch the throat of the ETC, after a few power-down moments, the ETC completely 'closes'.
In other words, with no power applied, the 'rest' position of the Duke ETC is 'fully closed'. Hmm... that contradicts 'a lot' of sensical convention (about preventing unwanted coast-down stalling or coast-down idle recovery-and-maintenance problems).
Do you understand my meaning here? Perhaps some of you have experience with this.
So, just playing killjoy for a second...
If the gears internal to the ETC were worn in such a way that the plate could just 'flop forward' when you dump the throttle... (but, ah, you'd notice that
all the time, wouldn't you?)
Or if the driver somehow got tired, intermittently, of holding the ETC open (but that implies an ECU fault, or an excessive ETC Volt/Amps current situation caused by a borderline ETC windings-integrity condition?)...
Or if the feedback sensor in the ETC told the ECU it was in a slightly erroneous position (but that implies a possible TPS design or production run fault)...
Or if the throttle servo motor just started acting a bit wanky when it got a bit too hot (and who doesn't? especially when forced to ride around all the time 'hugging' a live catalytic convertor)...
Well heck, all of this could even be attributed to an occasionally-skewed ground reference, fcs.
Ok, I'm driving myself nutz.
Please don't let me take you with me.
So without further adieu, maybe in these unique circumstances just related by discotrash and others, I wonder what would happen if we were to temporarily increase the insulation factor between the cat and the ETC unit. Again, it doesn't cost anything is what I'm saying.