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awyelton

Yamaha Moto 4 No Fire

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Just picked up a Moto 4 cheap, been sitting a few years, but had it running pretty quick.  Not sure on the year or size, haven't found where it's stamped at.  Cleaned the carb, replaced the fuel lines, cranked for a bit and had it running. Drove it around the farm a few times and then all of a sudden, it was as if you had reached up and turned the switch off. Replaced the battery, the old one was just something the previous owner had laying around. Also replaced the solenoid, as i just happened to have a new one laying around. So far the neutral switch light doesn't come on with the switch on and in neutral. I've checked all the connections I could find and fixed a couple of wires that were pieced together. I have 12v to the solenoid, and if i jump the terminals it will crank, just nothing when I hit the starter switch. As far as checking the regulator,coil,switch,etc. I know my way around a multimeter, just don't know how to check it out or any readings to look for. Any Ideas?

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Here  is the  ehow response to  an inquiry   on the  location of the   Moto 4 serial  number.  http://www.ehow.com/how_7552168_identify-yamaha-model-moto-4.html

Once you know the    year  and model  of your  quad  you  can search  on a service manual  for it .   In the  meantime ,  I would check  out the  ignition switch  and also  check to see  if there  is a  second relay   in the  circuit that    powers  the  system.  If the  ignition switch    isn't making proper contact ,  nothing will  work.    When  you   jump the   starter  solenoid , you  are  bypassing  the  ignition switch  and  main  power  circuit.  Does  the  motor start and run while  you  have the  starter  solenoid  bypassed and  die  as soon  as  you break the  bypass?  That would indicate  the ignition switch  or  a   main system  solenoid  if   used.

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2 hours ago, davefrombc said:

Here  is the  ehow response to  an inquiry   on the  location of the   Moto 4 serial  number.  http://www.ehow.com/how_7552168_identify-yamaha-model-moto-4.html

Once you know the    year  and model  of your  quad  you  can search  on a service manual  for it .   In the  meantime ,  I would check  out the  ignition switch  and also  check to see  if there  is a  second relay   in the  circuit that    powers  the  system.  If the  ignition switch    isn't making proper contact ,  nothing will  work.    When  you   jump the   starter  solenoid , you  are  bypassing  the  ignition switch  and  main  power  circuit.  Does  the  motor start and run while  you  have the  starter  solenoid  bypassed and  die  as soon  as  you break the  bypass?  That would indicate  the ignition switch  or  a   main system  solenoid  if   used.

Thanks for the info! Maybe now I can find the serial #.

Think I may have found the problem, went through all the wiring again today and found yet another wire that was pieced together. Fixed that, neutral light came on again, and she fired right up. Rode around for roughly 15-30 minutes without a problem and then it slowly died. It will crank and fire if I hold the throttle wide open, but won't stay running without WOT. Makes me think i may have sucked some trash out of the tank into the carb.

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OK..  Sounds like you found the problem.  Yes ,  new  problem sounds  like you  got  some  junk  into    jet  on the carb.   If it  has been sitting for a long time  I'd suggest  taking the fuel tank  off   and  putting some  marbles in it    Close  it  up  and  give  it   good shaking  so the marbles   knock  all  the  crud  loose in the tank and you  can  rinse it  out  and clean  it ..  You  may  have to replace  the  fuel  valve also.  They generally  have a screen  on them  that  may have deteriorated,  or may  have been damaged if you  left it  in  when giving the  marble  and shaking treatment.  Clean  the  carb, add some fresh  gas to a  clean  tank, and hopefully  you  are good to  go  for some fun riding.

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I have a 86 Moto 4 . There is a fuel valve just under the tank. May be that simple.

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Turns out it's a '86 225.  Flushed the tank, new carb, and new fuel switch on the tank. Starts up and idles like a champ. Problem is that it falls on its face when opening the throttle.

First thought was maybe the breaks we're  locked up (felt like it may have been grabbing).. Went trough all of that, and checks out. I adjusted the mixture needle to 2 1/4 turns from seated. Cleaned and checked the plug a few times, and it's black and sooty.Anyone know the correct setting for these carbs?

It seems to get worse as things get warmer. Since I discovered the spark plug boot is toast, going to go ahead and order a new coil.  I'm wondering if the coil is crapping out when it gets hot, causing the fouling  of the plug.

 

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18 minutes ago, awyelton said:

Turns out it's a '86 225.  Flushed the tank, new carb, and new fuel switch on the tank. Starts up and idles like a champ. Problem is that it falls on its face when opening the throttle.

First thought was maybe the breaks we're  locked up (felt like it may have been grabbing).. Went trough all of that, and checks out. I adjusted the mixture needle to 2 1/4 turns from seated. Cleaned and checked the plug a few times, and it's black and sooty.Anyone know the correct setting for these carbs?

It seems to get worse as things get warmer. Since I discovered the spark plug boot is toast, going to go ahead and order a new coil.  I'm wondering if the coil is crapping out when it gets hot, causing the fouling  of the plug.

 

Some video of what I'm dealing with.

https://m.facebook.com/story.php?story_fbid=1298844293518347&id=100001783662161

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I always have to tell my self to use the K.I.S.S. (keep it simple stupid) method when looking at problems for the first time. Check your air filter and make sure it's clean and in good shape : no mouse nests, holes or clogged with dirt. If that's all good turn your pilot screw all the way in and LIGHTLY seat it, then turn it out 2 turns. If it still runs rich turn it in 1/4 turn at a time until hopefully it smooths out. Give that a try. 

Yamaha Moto 4 YFM200DXW Service Manual.pdf

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8 hours ago, tjg358 said:

Sounds to me like your needle valve needs to be lowered. 

Bingo! Someone suggested that to me this morning, and it took care of it.

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One thing I forgot to mention, make sure your using fresh gas. If you are wondering at all if it's good, drain it and start over with fresh. Today's junk gas causes all sorts of problems.

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17 minutes ago, ddb171 said:

Thanks to everyone for all the input! I've still got some break cables to replace, and a few other odds and ends, so I'm sure I'll have a few more questions here and there!

      

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