Motorcycle Repair: 1980 xt500g yamaha electrical problem, voltage readings, switch battery

Question
My yamaha quit firing! I installed a new ignition coil and checked wiring continuity and voltage readings of ignition switch, kill switch, battery fuse etc. Now I have it in a repair shop. The mechanic checked these items too. He installed the new ignition coil and it fired a couple of times then quit. He said he tested the magneto/stator and thought it was ok. I think my problem is in the cdi unit my magneto/stator connects too, but I was told it doesn't usually go bad? I am having trouble finding replacement parts especially a cdi unit assembly! Are there electrical parts that might be interchageable from and sr500 or a tt500? Maybe you can help me pinpoint my electrical problem so I don't have to purchase unneeded electrical parts.

Need your suggestion

Mark Hardman  

Answer
Hi Mark,

It's tough to diagnose electrical problems without being present and performing tests.

Visit the foillowing website and use their Troubleshooting Chart: "www.electrexusa.com" or have your tech do this. I recommend their electrical components over OEM. Very high quality parts.

CDI's do indeed become defective and are almost impossible to test without the expensive factory diagnostic equipment. A common method for testing a suspected defective CDI is to test with a "known good" CDI.

Please keep me advised.

Respectfully,
Mark Shively