Not to resurrect a dead thread, but I just installed a new YTZ14S in my 2013 NC700X. I noticed it was similar to the YTZ12S that was in the bike, and had ordered the YTZ14S for my ST1300. I did a bit of measurement, and decided to install it. It went in smoothly, no problems. A bit more powerful battery, and it was easier to find one too. I use Chromebattery.com for my batteries, and get 4-5 years out of them. I DO use a desulphating trickle charger ( BatteryMinder) on a timer to keep them topped up. YMMV.
I did something similar with my 33 year old Dominator (NX). I had a spare YTZ14S battery from my X-Adv. and the Bosch battery already in the Dom was showing signs of fatigue. I have no idea how long the Bosch was in it but I guess many years. I initially set about trying to find as close to the original battery dimensions as possible but then realised I had the YTZ and wondered if it would fit. It measured up well but in application it was compressing the battery packing/insulation a little too much for my liking. Accordingly as the insulation was also very aged I replaced it with some new material but a little thinner. All is well ever since with no further dodgy starting after the bike has been lying up for a few weeks.