I just did my own 16,000 maintenance. new belt, installed 26g Sliders, replaced plugs with Iridium.
I had the bike on the center stand, started it up, let it idle for a minute or so. Everything was butter smooth. Idle is a little low like 1100 RPM. I will adjust it tomorrow morning back to 1300 when I change the oil/filter.
The issue I noticed was that the first time I revved the bike on the stand, when I opened the throttle it momentarily dropped out, like no combustion but then it gained revs fine and had no issues. Subsequent revving did not exhibit the same behavior.
I let the bike sit, turned off, for 5 minutes. Turned it back on and it did the same thing. It hesitated then fired fine. I took it for a test ride and never noticed any issues, in fact the sliders made a huge improvement in the smoothness of the acceleration and vibration.
Is this normal and I just have never noticed it before, or is there something that I should check out? I am thinking about running some sea foam at the next fill-up to clean the injectors. It could probably use it one way or the other.