Yes those are the ones I have. The bad part is that they are the wrong wiring diagrams. They are very different then mine. I will try to get into the shop today to give you answers to the other questions that you were asking. I will try multiple meters to confirm the results. I thank you so much for your efforts.

 

There are many different diagrams in those hundred and hundreds of pages. Look in the "manual 1997-2001" link download and extract the main manual. Then look in the "YFM350XJ suplemental" section near the beginning of the document (the second of many supplements) before the main manual begins. Page 11 shows the exact same wiring diagram you sent me. It is very legible and easy to read.

 

You are so very correct. I was looking at the one near the end. This is the one I have.

 

I wish I knew how to make that picture bigger. I can jumper the key switch (red to brown)and still get the same result. Anyway with the cdi unplugged and the key off I did some resistance to ground measurements and they are
8 pin plug
B - Gounded
Y/B - 75 ohm
BR/W - nothing
O - .9 ohm to ground - this one concerns me a bit but should it?
G/W - 1 ohm
W/B - 8ohm
B/Y - .6 ohm
B/W - nothing

Now the 5 pin plug
G/W - nothing as it should be as the switch is open normaly
W - nothing
BR - 1 ohm
G - nothing
R - nothing

 

I think I may have got the picture bigger now.

 

I am having the same problem with the no spark!!! I get a single spark when I let go of the start button after cranking for several seconds. Mine is a 87 and I have replaced the stator, CDI, and coil. Still have the same problem, no spark. This all started happening when my stator bolts worked loose and stator started rubbing in flywheel housing.

 

The 0.9 ohm coil primary reading (orange wire) sounds high to me. What you are measuring is the resistance of a few hundred turns of wire in the ignition coil to ground (plus the resistance of the wire from the CDI connector to the coil, the ground return path, and the resistance of the meter leads themselves). All my experience with chinese quads has shown the primary resistance to be less than 0.5 ohms. The Yamaha service says it should be 0.36 to 0.48 ohms. You may want to measure the ignition coil wire to ground at the coil itself (per the service manual instructions) to eliminate the wiring harness resistances. Also measure the resistance of the meter leads when shorted together. Does it read zero ohms, or something else like 0.2 ohms?

You said you changed the ignition coil. Does the old coil primary side resistance measure the same as your newer coil? You may have two problems. If one of your new installed parts is bad then you could easilly go in circles.

To review:

You have 79 volts AC ignition power from the stator to the CDI. You have 0.4 volts AC trigger signal voltage from the stator to the CDI. You don't see any output from the CDI to the coil, and the coil primary resistance is reading high.

Somewhere along the line you went from no spark, to one weak spark when the starter is first engaged. This is strange. Swapping a good part for a good part will not fix the original problem, but it should also produce identical symptoms. But swapping in a bad part into an already bad system can produce a change in the symptoms. I would change back in some of the swapped out components (like CDI and ignition coil) to see if there in any consistent change is symptoms that follows a part. There are clues there.

It is also probably time to start fresh and revisit/remeasure all the steps you've taken so far. A mistake early on leads to following proverbial garden paths that lead nowhere. The only way out is to backtrack, verify or discredit earlier results, and then move forward from there.

 

Ok here is what I have found so far. I can try to push start the atv and get the same results with the one spark. After closer examination the spark is pretty good with both the electric start and push start but just one initial time.

I tested the multimeter with the leads together and it does zero out.

Went back to the original harness with the same results. The orange wire at the cdi to ground at the secondary coil is .5 to .6 ohm. It is also much warmer in the garage this time that I am testing. The wiring harness is not giving me any resistance from the orange wire at the cdi to the orange wire where it comes out at the secondary coil. So that part is good.

The secondary coil from the spark plug lead to the ground is 6.06 K ohms.

Spark plug cap is 5.46 K ohms

Kill switch from black to black/white is no resistance when in off position and open when on
Park switch disconected as it should be open anyway.

Not that it has anything to do with it but clutch switch is disconected and the black and black/yellow from the harness are connected together to simulate the clutch is pulled in.

On the key switch from red to brown open when key is off and .2 ohm when key is on.
On the kew switch from black to black/white .2 ohm when key is off and open when key is on.

 

After thinking about this, the one spark when the starter is engaged is the most puzzling. I'm thinking the CDI has to be the culprit. Its firing once then not firing anymore. That could happen if the internal SCR stays on after the first trigger. Then the storage capacitor (the "C" in the CDI acronym) can never charge back up and you would see a very small AC voltage at the ignition coil primary - which I believe you reported earlier.

You have replaced the CDI. Does the previous CDI do the same thing - i.e. you get one spark when the starter is first engaged and then no more spark? Or do you just not get any spark at all? If both your CDIs are good then they should work identically. If one or both bad they may or may not.

Can you get back to the point where you didn't have any spark at all instead of one spark? That could be a clue...

 

By no means am I and expert on Yamaha ignition systems. I normally work on chinese quads and spend all my time over on those forums. Since no one else has stepped in I will tell you what I would do in your case.

Getting one spark when the starter motor is disengaged suggests a missing or weak trigger to the CDI. The signal comes from the pickup coil outside the flywheel in the stator. It tells the CDI when to fire. If this signal is missing or weak the CDI won't fire and there will be no spark.

But when you turn the starter motor off you are interrupting a large current to an inductive device and huge electrical transients are generated. This can be enough to trigger the CDI once as the starter disengages.

I would get the service manuals listed earlier in this thread and follow the ignition troubleshooting procedures. In particular note the stator pickup coil tests. Also inspect the trigger pickup coil for embedded steel debris at the sensor face (removing it if found), and make sure the gap is not too wide between the pickup and the flywheel raised bump that flys by as the engine turns.