o1 yz 125 will not stay running

11 replies to this topic
  • punkies7

Posted July 17, 2007 - 06:06 PM


my 01 yz 125 will not stay running. it will start `1 kick and idle fine. runs good until i really get on it then it completely shuts off. it doesn't bog or sputter just cuts off all at once. then starts right back up immedietely I cleaned the carb and all of my jets, wondering if maybe it could be electrical, and how to find out.....

  • Yamaha4lyfe

Posted July 17, 2007 - 08:51 PM


get a tester and try with your coil see if its jumping or mis sparking, check your cdi your manual will tell you how to do this

  • FiftySeven

Posted July 17, 2007 - 08:52 PM


are any of the hoses clogged up ?

  • norcalmoto285

Posted July 17, 2007 - 10:02 PM


look at your jets. i had the same problem with mine and i got lucky with a clogged jet.

  • Denn10

Posted July 18, 2007 - 06:02 AM


Does it cut out if your just revving the engine up? If you havent tried this check it out . I would say if it is only cutting out when your riding then you should look at connections like a loose bolt on the coil or something like that maybe. But see if it only dies when moving.

  • alex211

Posted July 18, 2007 - 06:31 AM


Also is your jetting lean or rich? And how long have you been having this problem?

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  • InsaneMXer450F

Posted July 18, 2007 - 07:24 AM


Are you sure the gas is turned ---> On <---

  • cuddies say YEE 925

Posted July 18, 2007 - 07:30 AM


Sounds like it dies under load. First thing I would do is buy a new spark plug- same problem just happened to my buddy with his 97 YZ125.

  • Vinny2692

Posted July 18, 2007 - 06:18 PM


i dunno, just throwing it out there. Is it getting anough air?

  • Deathsled69

Posted July 19, 2007 - 06:31 AM


Call up a mx store that is by you and tell them what is going on then they might know whats up. you should clean your sparkplug and check your gas mix make sure its not to strong.

  • Rootuser

Posted July 19, 2007 - 04:35 PM


What to check from easiest to most difficult:

1. Gas
A. Is there gas in the tank?
B. Is the gas flowing into the carb? Pull the gas line and check.
2. Spark
A. Is the spark plug good? Are you getting a nice strong spark? Is it weak?
B. If the spark is weak, remove the cap and push the plug right into the wire itself. Is it still weak? If not you've got a bad cap. If it is you might have a bad plug or something wrong electrically.
3. Pull the air-cleaner and run it in the garage TEMPORARILY without it. Does it suddenly run better? If so, clogged air filter. DO NOT RUN THE BIKE WITHOUT THE AIR CLEANER FOR ANY REAL LENGTH OF TIME.
4. Carb. Crack the float bowl and make sure it's got gas in it. If not it's clogged. If its over-flowing then it's got something else in the carb clogged. With the bowl off let the floats down, does the gas flow? If not, something is clogged. If all of these look ok, then you could at this point pull the carb off and give it a real cleaning just to be 100% sure.
5. Start tracing wire. Make sure nothing is cut or a wire is hosed. You can also pull out an Ohm meter to test the different parts (Rectifier if so equipped, Coil, stator etc).

Those are the top 5 and the order I personally use to do quick troubleshooting with running problems. Since yours may be an under-load issue, it could be any of the above. Is it the MINUTE You put it in to gear or will it rev in gear fine on a stand but dies when you sit on it?

-- Rootuser

  • howell

Posted July 19, 2007 - 06:47 PM


did this problem just start. if so it might be the gas like said before or a jet. check this post^^^^

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