I bought a 2011 Multistrada 1200S in Sept of 2018. Just as I was getting used to all of that raw, de-tuned 1198 power, I noticed that the engine wasn't running right Here's a list of the symptoms:
Backfiring when letting off the throttle
Misfiring especially when at lower RPM while under load (moving from a stop)
Shaky engine power - It tries to rattle my teeth out, then seems to smooth out past 4k RPM. I know that this is a common characteristic with these engines, but it's getting progressively more shaky and I think it's related to the issue.
High idle - This started happening about a week ago. The actual RPM varies, but it's been sitting at 2500 at times. Weird note: when I shift into neutral, it returns to normal idle RPMs.
If I blip the throttle on and off quickly, I can get the engine to stall out.
Getting worse day-by-day and seems to be particularly bad in the rain, but still a problem on sunny, dry days.
I tore into the bike and looked at the spark plugs. The vertical cylinder's plug looked light brown. The shop manual says this is a good thing. The horizontal cylinder plug was black, which seems to confirm my suspicion that it's running a bit rich. I also found that the coil was allowing water and dirt past the grommet, as the coil was weeping rust and there was dirt/clay around the bottom of the slot the coil sits in as well as moisture.
I replaced the coil with a used one to troubleshoot it. I was convinced that would fix it, and was heartbroken when it didn't.
I think it's also worth mentioning that I replaced the spark plugs, as I don't know how old they were. I made sure I replaced everything with the appropriate parts and verified the part numbers with either the manual or the Ducati website. I also checked the plug gap, even though I knew that they come pre-gapped. I don't have much experience with this kind of work, so I tend to over-verify everything.
Basically, I'm at a loss. I have a few ideas of other things I can check, but I'm hoping that someone else has had a similar experience and/or can help guide me in the right direction.