1987 yamaha 350 big bear

[Mikey]

I have like I said a 87 350 big bear atv!! It has always for all these years been the only thing in the door yard that I could jump on always started up and worked the way it should!! Untill now, first it was the carb, float ad needle sticking, got that fixed!!! Then in the process of trying to get the carb reset I got a no spark issue!! Got my aftermarket tec manual out, that works well if you are working on some thing mechanical, not so much for wiring and electronics, no color codes!!! Ride off the bat I started at the spark plug, coil has a open winding, crap, so got a new coil, installed, tested for spark, get one spark just as the starter buttons pushed then no spark, crap!!!! Now I have to dive in deeper with my test, stator, well luckily I found a web site that gave me a Yamaha tec manual with the color coding I wanted, stator it self tests ok, but the two pick up coils are open, Crap!!! Now I go on line and check out the parts that I know I need! Stator, regulator, they have, I just don't know about the cdi box, can't test it, and can't find new or aftermarket!! Crap, is that because they never go bad or is that the sigh to use it for a boat anchor? If the regulator over charged the system took out the stator and coil would it kill the cdi box? Don't want to buy the parts I know I need to find out that the dam cdi box is bad and I can't seem to find it yet!! I know there is a lot of good motor heads on here and wanted to bounce my thoughts off you guys!!!! Thank you for your time,
Mike B

[Grandpot]

Like you, I keep things a long time (been married 44 years). The bad thing about older electronics is the insulation breaks down over time. Unfortunately you can't test the output of the electrical supply devices unless the motor is running, so start with some simple checks. If the battery is fully charged, the engine should start, even if the alternator is defective. Check the wiring from the battery to CDI. If the CDI is getting 12V, check the input and output pulses. Check the wiring for the input and output pulses of the CDI. If that's OK, then you still have a problem further down the line toward the Coil.

If you see any cracked insulation on the wires, replace the wires. Make sure nothing is going to ground. You have a lot of work to do.

[SpyderConvert]

I rebuilt a 1967 Triumph Bonneville and one of the first things that I did was to remove all of the Lucas wiring. I took out the battery and replaced it with a cdi (capacitive discharge ignition). Once I got it wired right, it worked perfectly. Maybe I am misunderstanding what the OP was referring to about the cdi, if I am, please correct me, it was 40 years ago when I did this.

[pegasus1300]

Maybe this will be of some help. https://www.quadcrazy.com/atvforum/t...w-to-test-cdi/