1 probably ,you have not repointing linux to your kernel
cd /usr/src && rm linux
ln -s /your kernel/ linux <----this is the problem
2 from 2.6.x up you dont need to copy bzimage...
after make oldconfig , " make install "will do (and make modules_install of course)
3 look at Makefile and see the version number,addendum...
at the beginning (you can even put extension_funny_names
so later uname -a gives "president of virtual USA" )
4 after make install ,check grub /lilo
normally with grub the make install modifies for you already
pointing link to new vmlinuz and systemmap
just reboot and cross fingers