The stator out put and the external (secondary) coil can be checked w/ a volt/ohm meter. the CDI cannot be checked. yellow wires are for acc. like lights. the charge coil wire is usually white and red, or just red and the ground is the black one. you should have power at those wires when pulling it over. (A/C voltage) the secondary coil can be tested at a dealer, it is usually free if you have any kind of relationship with them. the CDI can only be replaced with a known good one to test.
like the previous posts, make sure all the switches are functioning properly.
