If it's not the plugs or leads....?? Have you checked/replaced the fuel filter & fuel lines?? You don't have a blockage or kink in any of them, or maybe a blocked fuel tank breather do you??
Yeah, I know it's a bit out there, but you mention a sickly sweet smell coming from the charcoal/evap canister.... (& they are actually meant to be a 'service by replacement item' too -ever replaced one?!) My bike has just had a replacement canister fitted under recall because many others (not mine) had (amongst other things) power loss & missing problems similar to those you describe.... The other symptoms reported included (amongst others & in no particular order): flooded/defective & smelly charcoal canisters; deterioration &/or blockages of the fuel filters & hoses; leaking & overflow of fuel thru the canister onto the ground after re-fuelling; & even a few total loss events due to bikes catching on fire & burning completely!! Some of the 'possible contributory factors' blamed for this happening to some & not others included "occasional 'over-filling' of the fuel tank" leading to the charcoal canister being flooded by liquid fuel instead of the expansion vapours it was designed to trap; & fuel filters, hoses etc being at least partially blocked or damaged & deteriorating due to contaminants in the fuel; but almost all who had the base issues reported 'missing or jerking in power delivery & engine running at certain speeds', sorta like what you've reported here... And when you think about it, a partially blocked fuel filter, hoses, or vent/breather system on/in your fuel system is very likely to cause some hesitation/missing, innit!!
Might be worth a bit of effort in checking it all out, replacing filter/s etc, & maybe even getting a different charcoal canister (new if not too expensive, or 2nd hand if it is) to see if it makes a difference. I hadn't ever had any of the issues others complained about on their bikes leading up to the recall, but the new canister & other recall work has improved my fuel economy & possibly also the mid-range power (haven't checked that tho, it's hard to run it on a dyno!!)
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