So I've changed my air filter, engine coolant and spark plugs (the oil was changed < 1000 miles ago along with the filter so I'm leaving that for now) and the engine sounds... different!
It doesn't sound "bad", but "more aggressive"... a bit louder and more "throaty".
Am I right in thinking this is because of the super clean filter? The old one was a year overdue for changing and really clogged up with crap (spark plugs were also overdue for changing and had heavy carbon deposits on them all), so I'm thinking what I'm hearing now is "an engine with better airflow and better combustion".
I mean, if it were (hypothetically speaking) a spark plug not firing at all or not firing quite properly, would the sound be "obvious" in that case? Like a backfire noise or something? Also, in that event would I not get a warning light on the "dash" and FI failure codes in maintenance mode? Would it even turn over if one of the spark plugs wasn't working properly? I don't know how "smart" the EMS is on this bike!
If necessary I can record a short sample of my engine sound when turning it over and revving her up.
Note: I haven't yet test-ridden the bike. I'm going to do that in the morning (with the Mrs trailing in the car with my tools in case anything goes wrong). The bike fires up and idles beautifully, there's no "smoke" or any visible "crap" coming out of the exhaust, and the engine is taking a fair while longer to get its first bar on the temp guage - which you'd expect with a clean rad and fresh coolant). It revs up smoothly and seems to "drop off" abruptly when I close the throttle (probably normal, never really paid much attention to the "drop off" before).
Anyway, I've been as descriptive as I can so I'll wrap this up, but if anyone has any thoughts or ideas (and especially answers to the questions) that's appeciated