A 113 would be an insult. Honestly they could keep the displacement at 110 and make big power improvements with compression bumps, cams and tunings.
The target audience wouldn't realize only three cubic inches isn't a big deal, so a 113 would impress those folks. People that actually know something about these engines would probably be more interested in seeing some quality and reliability improvements much more than a larger number on the air cleaner and timer cover decals, if you know what I mean.
In the past H-D has upped displacement in increments of about seven cubic inches. So if we assume they continue that pattern, we might see: 80 - 88 - 95 - 103 - 110 -
117. On the other hand, now that they've gained the blessings of the EPA and CARB for the 120, why not just jump straight to that? The 120 will fit many previous model years, so they would still have a huge potential market for the upgrade, and the top offering would once again be the same as what they put in the CVO's standard. Seems like the easiest and cheapest way for Harley to go, rather than add another engine size between 110 and 120.

Jerry