A C24 is a problem with the voltage reading at the front ignition coil. Sometimes, especially on bikes ridden on salted roads, there is a problem with the crimped wire connection to the coil corroding. A way to check is to connect the black/orange wire on the front coil to an orange/white wire at the rear coil or at the fuel pump relay. If that fixes the problem, you'll know the crimp connection of the B/O to the O/W wire in the loom has corroded.