Help with Yamaha Moto 4 350cc

[Charlesawest936]

Good morning, I'm really at the end of the rope with this bike. If someone can give me any other ideas I'd really appreciate it. I have a Yamaha Moto 4 350cc 2x4 that I got for my step daughter and I can not get this thing to fire except for 1x each time I either turn the key off or if I let it sit a few mins in between trying to start it. I'm not exactly sure what year it is because I haven't been able to find the vin number yet on it. What iv done so far is, checked ohms on the stator and all 3 white wires go to .001 no connection to ground like it shouldn't. My cdi is new and getting the same results with the old 1 as well. On the cdi iv got 2 plugs and 3 single wires. The singles are orange that goes to the coil which is a known good coil because I took it off of my Kodiak that runs and put the old coil back on the Kodiak which still runs. There's a single red wire and brown wire which goes to the source coil on the stator when checking ohms on it it shows .303 ohm's the blue and white wires for 1 of the pick up coils shows .199 ohms and the other pick up coil green and yellow wires shows .200 ohms so all are within factory specs. Iv changed the ignition switch and the neutral light does come on like it should but I'm still only getting the single spark when you first try starting the bike. Any ideas? Oh iv also changed the rectifier regulator also. And when checking for spark I'm putting the plug wire close to the head bolt without the plug or cap on the wire 

[jftucker1981]

Classis

Classic

[gatorschevy]

I just picked up a moto4 I also have no idea what the year is they say the vin is on the frame left side by the foot peg, cant find mine but yours might be there, but I am getting ready to pull the plastics, so maybe there is something i can do to help you when i do

[gatorschevy]

found out what year mine is because its grey so i guess this makes it a 92

[Mech]

Hi Charles. This problem has been discussed in her before, if you do a search for the symptom (one spark), you may find something useful.

What I'd do though is check that all the feeds from the stator, and the trigger coil, are getting all the way to the cdi. You could check with the ohm meter or if you have one, use an old fashioned analouge voltage gauge, at the cdi.

The cdi takes the voltage from the source coils and stacks the voltage up on top of one other to give a higher voltage, it could be that only one of those two source coils is getting through. It's possible that the cdi is counting source coil pulses and only triggering after it knows there has been two full rotations of the crank after a trigger pulse. If one source coil's not getting through it will throw the cdi's calculation off.

[gatorschevy]

found my vin it's under the oil lines on bottom of frame