Jeds

What's involved in rebuilding the cdi box? Is it something I could do with some direction or is it complex and would be better off getting a replacement?

I have a 1973 MX175 and I believe that I need a new CDI or Magneto; my question is does the replacement part need to be from the same year and model or are there any others that would fit or work? Any expertise would be appreciated...Thanks.

I have recently acquired a 1973 Yamaha MX175, I have no spark, I don't know much about the electrical systems on dirt bikes..What is the best way to troubleshoot the system? and if needed where would be a good place to get cheap replacement components like the magneto and CDI unit? Any help would be appreciated..Cheers!