No spark

[slayed]

I just bought a used 88 kdx200 and it has no spark. How do I diagnose this? I put a test light on each of the three wires. Only the red/white wire lit up. The black wire nor the yellow wire would make the test light light up when I hand turned the kick start. Should they?

[bufftester]

Yellow is the lighting coil lead, should have voltage there when turning over the motor, but it's AC. IIRC these models didn't have a voltage regulator. That's separate from your ignition circuit, however. THe white/red is your timing pulses to the CDI. FIrst thing to do is go back and recheck all your electrical connections to ensure they are free of corrosion. Then check your grounds to ensure the same. Then check the engine kill switch as they can be a problem on these older bikes (you could just bypass it for testing purposes). Then recheck for spark at the plug. If nothing there work backwards from the high tension lead. The Black/yellow coming out of the CDI tot he coil would be the next place to check, if you have voltage there replace the coil. if not it's likely the CDI.