Battery is 2 years old.
Registers a full 12 V on the multimeter.
At 25 degrees the starting process chugs along but doesn't turn over the 117 CI until I hook up a portable mini jumpbox.
Do I need a battery with more CCA?
If the battery is 2 yrs old, you may not still be getting a true 310 CCA
Have the battery load tested.
CCA is a "standard" test but is misunderstood by most people and not even just 1 standard for it.
Discover why a good CCA reading does not always guarantee a good battery
batteryuniversity.com
Load testers as used at battery shops are doing best guess, not truly testing CCA, but using some math to estimate.
Make sure when trying to start in cold that you do not hold the start switch very long (3 sec at most)
Any lead acid battery that claims over 350CCA for a battery that fits our bikes is BS imho. The ones that claim that certainly are not truly testing it according to spec. If that capacaity were possible, why wouldn't the real manufacturers (East Penn, Yusua etc) advertised it directly. The ones you see are made by them in reality but marketed and labeled by someone else.
Lately I have been using the Duracell from Batteries + Bulbs. If you buy online and pick up in store it 10% off, plus they offer a 2 yr warranty (an they are all over the place).