2009 YZ450 won't stay running after it warms up


38 replies to this topic
  • grayracer513

Posted January 27, 2015 - 04:04 PM

#21

I'll try that. If that's the problem though, why would it start right back up? Wouldn't it not start until it cools off?

 

I learned a long time ago that an intermittent electrical fault can do almost anything it wants to, and probably will.  I stopped trying to make sense of every single condition.  The hardest part about them is trying to catch them when and while they are actively at fault.  Otherwise, you're down to guessing and troubleshooting by substitution, which gets awfully expensive, since electrical components are not returnable, as a rule. 



  • Yzrider1023

Posted January 27, 2015 - 08:36 PM

#22

Try a new spark plug my bike did the same thing and it was a bad plug

  • pastranafan5

Posted January 27, 2015 - 09:35 PM

#23

I was thinking about buying it. That bike has a brand new head And valve train. If I'm not mistaken a new top and bottom too. Are you in MS? I'm in Oxford. If you get it right we should ride!

I'm in Jonesboro, AR. I plan on riding over at Covington soon.

  • pastranafan5

Posted January 27, 2015 - 09:41 PM

#24

Try a new spark plug my bike did the same thing and it was a bad plug

I put a new plug in it. Its black already.

Edited by pastranafan5, January 27, 2015 - 09:41 PM.


  • Yzrider1023

Posted January 27, 2015 - 10:05 PM

#25

I put a new plug in it. Its black already.


If it's black already your probably running a little rich if I'm not mistaken you should probably just tear apart the carb and give it a very good cleaning from top to bottom and change your jets also see if your accelerator pump is in good shape

  • grayracer513

Posted January 28, 2015 - 07:37 AM

#26

A black sooty plug can be caused by faulty ignition, even with perfect jetting.  Also remember that unless the plug is allowed to reach operating temperature and stay there for at least 5 minutes, it will not turn dry and tan looking. 



  • JS264

Posted January 28, 2015 - 07:45 AM

#27

Use an inline spark tester to see if you are losing spark when it kills.

  • Will.A.R.

Posted January 28, 2015 - 12:09 PM

#28

Jrice2012 where in Mississippi. I just bought an 09 in Mississippi I'm rebuilding.

  • jrice2012

Posted January 28, 2015 - 02:01 PM

#29

Jrice2012 where in Mississippi. I just bought an 09 in Mississippi I'm rebuilding.

the Op owns the bike I am referring to. It was bought in Southaven. I live in Oxford, but mainly ride at a few tracks in tupelo and Pontotoc. Sometimes go down to Jackson for the jetwerx compound. Where you from?

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  • Will.A.R.

Posted January 28, 2015 - 02:49 PM

#30

Columbus. I ride at 886, vet, Booneville. About everywhere. We've probably crossed paths. Im a slow vet rider on an old yz450.

  • jrice2012

Posted January 28, 2015 - 03:57 PM

#31

Columbus. I ride at 886, vet, Booneville. About everywhere. We've probably crossed paths. Im a slow vet rider on an old yz450.

I'm riding vet Saturday. Did you race Booneville back in September? We Probably have crossed paths. I'm on an 08 yz450

  • Will.A.R.

Posted January 28, 2015 - 04:13 PM

#32

We hit a couple races up there. One got rained out after first moto. We racing at Longhorn Arena Sat up in Muscle Shoals

  • jrice2012

Posted January 29, 2015 - 08:58 AM

#33

We hit a couple races up there. One got rained out after first moto. We racing at Longhorn Arena Sat up in Muscle Shoals


Muscle shoals is a good ways from me. Did you race the Starkville arenacross this past Saturday by any chance?

  • Will.A.R.

Posted January 29, 2015 - 08:59 AM

#34

A couple from our bunch was there. Both my bikes are down currently

  • jrice2012

Posted January 29, 2015 - 09:05 AM

#35

A couple from our bunch was there. Both my bikes are down currently


The guy that bought my old rmz was there. He was from Columbus. I think he said he had a track at his place. I think his name is Jason? There was a girl rider with him too. I THINK her name was mckayla. She had a yz250f, and then some guy on a 125. Would that happen to be your bunch? Haha

  • Will.A.R.

Posted January 29, 2015 - 10:37 AM

#36

Yep!! U met me. I was the big guy

  • jrice2012

Posted January 29, 2015 - 10:44 AM

#37

Yep!! U met me. I was the big guy


Oh okay! Small world!

  • pastranafan5

Posted March 18, 2015 - 07:44 AM

#38

Here's an update on my bike problem. It finally got warm enough to check it out. I checked my ohms and found out the spark plug cap was bad. $20 later for a used spark plug cap and the bike runs fine. Thanks so much for the help. I never would have guessed an electrical problem.



  • Henrylight

Posted March 18, 2015 - 04:09 PM

#39

Mine did the same thing until the rod came out of the case run good gets some heat stall out fast cool off and run good and then new motor





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