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Hey y'all. I have a Yamaha ymf 250 BearTracker. I got this thing for free from people whose son tore it to hell. So it wasn't in great shape to begin with. i.e. no indicator lights (neutral light for instance), no ignition switch or key( wires were twisted together to make it run), get the picture yet?
So when it ran it ran rough and I got it running for a year or two, just something fun for the kids to ride on with me on gravels.
Now just randomly, the start button stopped working so I had to jump the solenoid, then put a temp start switch in. Kill switch would still work.
However, the thing has no spark what-so-ever. I've check continuity through the start button and it shows the contact is working, ohmed out the stator, everything is in spec, the reg/rec tested fine as well. I've replaced the solenoid on the off chance it could've been bad and the cdi unit as well, along the the little solenoid relay unit. I'm still getting no spark. The spark plugs is new as well and the coils to the plug have been tested and are good. I've tested and trouble shooted everything I can on this quad and no luck. I watched countless YouTube "no spark" situation videos and it's not helped. Does anyone have any tips or tricks I could try? Would really appreciate some input on this. Thanks!
 

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Check you have continuity between engine/ frame & ground terminal on battery. Don't forget the elect. has to get back to the battery! I had on/off bike dying on me & eventually found it was the ground wiring inside the loom ; all the wires collect together & a connector had corroded.
 

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Check you have continuity between engine/ frame & ground terminal on battery. Don't forget the elect. has to get back to the battery! I had on/off bike dying on me & eventually found it was the ground wiring inside the loom ; all the wires collect together & a connector had corroded.
You mean unraveling the harness and looking at all of the wiring? I was dreading that this would be said lol I have NOT dont this but I guess I need to.
 

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You mean unraveling the harness and looking at all of the wiring? I was dreading that this would be said lol I have NOT dont this but I guess I need to.
Run an external wire from engine casing to negative battery terminal. If that fixes it you can leave it in place & motor on!
 

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There is only 7 things that will keep it from firing.
coil
plug
CDI unit
firing stator
start relay
Kill switch
wiring
ymf250 diagram (https://www.quadcrazy.com/uploads/m...ED.jpeg.cbc2756f30d669697ae26029547f852e.jpeg)
The main switch has 2wires going to it. Positive from battery(fused) Red wire, and a Brown wire which is connected to the head light switch, the run/stop switch, the neutral safety switch, rear brake switch, and the reverse switch. Now if the neutral safety switch or rear brake switch is made it pulls in the starting circuit cutoff relay allowing the starter solenoid to have 12 volts from the run stop switch so when the starter push button is pressed the starter turns engine over (Note the run stop switch sends a 12 volts to cdi unit so it can operate and starting circuit cutoff).
If all the wiring to the switch tests good then go to CDI unit and check the red/black and see if it has a 12 volts at the connection( it should be 12 volts in run mode) and If it has 12 volts then any time engine is turned over the ignition should fire if the CDI unit, Stator and wiring for them is good. .
 

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There is only 7 things that will keep it from firing.
coil
plug
CDI unit
firing stator
start relay
Kill switch
wiring
ymf250 diagram (https://www.quadcrazy.com/uploads/m...ED.jpeg.cbc2756f30d669697ae26029547f852e.jpeg)
The main switch has 2wires going to it. Positive from battery(fused) Red wire, and a Brown wire which is connected to the head light switch, the run/stop switch, the neutral safety switch, rear brake switch, and the reverse switch. Now if the neutral safety switch or rear brake switch is made it pulls in the starting circuit cutoff relay allowing the starter solenoid to have 12 volts from the run stop switch so when the starter push button is pressed the starter turns engine over (Note the run stop switch sends a 12 volts to cdi unit so it can operate and starting circuit cutoff).
If all the wiring to the switch tests good then go to CDI unit and check the red/black and see if it has a 12 volts at the connection( it should be 12 volts in run mode) and If it has 12 volts then any time engine is turned over the ignition should fire if the CDI unit, Stator and wiring for them is good. .
Thank you for this! I'm no good at reading these diagrams but my uncle will be over for my july 4th cookout tomorrow and I'll have him decipher it for me haha. With a brand new kill switch, key switch, stator, cdi, coil, and spark plug makes me think that the issue is most certainly in the wiring somewhere. Are you saying that if the brake switch isnt made then there wont be fire or that it just wont let the starter engage?
 

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OK if the brake switch and/or the neutral switch is made it will allow starter to turn over and give the cdi unit power so it can fire. But if the cdi unit has not got the 12 volts on the red/black wire connection at the cdi then the cdi will not fire. It gets it's 12 volts from the Brake switch or the neutral safety switch if there is not a broken wire somewhere.
 

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OK if the brake switch and/or the neutral switch is made it will allow starter to turn over and give the cdi unit power so it can fire. But if the cdi unit has not got the 12 volts on the red/black wire connection at the cdi then the cdi will not fire. It gets it's 12 volts from the Brake switch or the neutral safety switch if there is not a broken wire somewhere.
Appreciate the clarity!
 

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Another thing crossed my mind lol The plug in connectors to the CDI, stator and switches sometimes corrode and causes bad connection. Cleaning them can be done using a small wire brush and electrical cleaner. After they are cleaned get some electrical connection grease and put on the terminals before plugging them together.
 

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Another thing crossed my mind lol The plug in connectors to the CDI, stator and switches sometimes corrode and causes bad connection. Cleaning them can be done using a small wire brush and electrical cleaner. After they are cleaned get some electrical connection grease and put on the terminals before plugging them together.
I unplugged them all and they looked okay except the one to the rectifier. It had what looked to be something wet and sticky. When I pulled the connector off it pulled stringy stuff out that stretched like melted mozzarella lol I'll clean all the connections anyway just in case
 

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Idk if it's okay to come back to old posts or not but I never figured out my 2004 beartracker no spark issue. Mainly because I quit fooling with it. Too many projects. I pulled it back out today and realized something new. With the key on i can put my voltmeter in the hot wire that plugs into the ignition coil and ground the other end and get 9 or so on the meter. Once I plug the hot wire into the coil, the meter goes to zero. Im not good with electricity but it seems like if everything was good then everything would stay the same whether it's plugged in or not..?
 
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