Greetings,
I am purchasing a 1990 Fourtrax trx 300 4x4 that is blue in color. Looks to be n good shape, but has quit running. No spark. I have not had an opportunity to start troubleshooting it myself. The person who owns it has told me that a mechanic has worked on it a couple of times and cannot figure out why it is not getting spark. I have little experience with ATV, but tons of experience in the auto and 4x4 world. I have been reading about the common electrical problems with these atv's, and it looks like an obvious component to go bad is the CDI. My question is this;
How do you test the CDI? I do not want to blindly go changing parts, but I would rather check and make sure the CDI is functioning properly.
I know I need to check the grounds, and I will be replacing the plug and plug wire anyway. Is there a step by step checklist somewhere for troubleshooting ignition systems? I will be buying a repair manual as well. Which one is recomended?
Thanks for helping!

Mike