I have a 2006 YFZ 450 and it will not start. I tried charging the battery, no luck. I tried another battery, same results. I took the spark plug out and I see that it is not getting any spark when it tries to turn over. I hooked the test light up to the coil plug and it is not getting any power. Next step is to test the cdi and see it it is sending a signal to the coil. Does anybody know how to test the CDI Unit?

 

If I take the CDI off then I should get constant power to the coil?

 

theres really no way to bench test a CDI,at least not accurately.... the only way to rule it out is to eliminate everything else as the troubled component or swapping out with a known good CDI, most likely if it has no spark at all....even when jump started, skid started and just no spark at all it prolly is the CDI....best thing i can tell you to do if you cant borrow a friends cdi or get a dealer to let u swap them real quick just for assurance is to test everything else but the coil...leaving that as the only culprit....get a multi meter out testing with resistance values in ohms on the trigger coil, source coil, black box and ignition coil.