Are you 100% sure that the dealer put that new Yuasa battery on a proper charger for
at least 8 hours immediately before installing it in your Spyder??

And does that new Yuasa battery have at least 350 CCA & 21 A/hr capacity??
There again, even brand new batteries can die,
especially if they've been installed with less than a full & proper charge &/or they've just got too small of a capacity for the job being asked of them.
Ps: Those Kill Switches are anachronisms left over from the days when motorcycles had exposed spark ignition systems sitting on top if the engine immediately below the gas tank and that often gravity fed gas out thru a stop-cock in the bottom of the tank directly into the open bowl carby/s that kept then engine running. They are now FAAARRR more of a liability on a modern fuel injected ICE motorcycle/trike, especially since most of the time there's a bunch of failsafe electronics that immediately stop the gas being pumped into the engine cos said tank is no longer immediately above the engine (but rather, usually behind and on the same level if not below all the spark sources!) & nor is the gas gravity fed into an area very near an ignition system that's likely to provide an ignition source for any spilled/leaking gas! You don't have an extra 'Kill Switch' on your modern auto, simply because they don't need them and they produce more issues than the supposed risks they 'protect' against &/or minimise - so why the bleedin' 'eck are they still mandated for things like our Spyders!