Hi tlapsley,
Have you tried to run:
make image
Before building kernel? You need to run this command only once. After that you can:
cd poky
source ./oe-init-build-env
cd ../../build_bin
bitbake -c cleanall linux-yocto (to clean)
bitbake linux-yocto (to build it again)
bitbake -c compile linux-yocto -f (to force kernel compilation)
etc.
You can read more about bitbake commands at https://www.yoctoproject.org/documentation/bitbake-user-manual-0 .
Please, let me know if you have any other questions.
Best regards,
Dragan