Yamaha 450 won't start



6 replies to this topic
  • Dasboone

Posted September 13, 2014 - 05:49 PM

#1

My 07 Yamaha 450 died on a trail ride. I was able to bump start it, but ran like crap. I changed the fuel, plug and verified the timing was correct. It will intermittent start and run with no consistency. When it runs everything is normal and then it will die and will not start. It has spark, is getting fuel and seems to want to start but will not run. I am thinking it is the carb. Any ideas?

  • Krannie McKranface

Posted September 14, 2014 - 04:15 AM

#2

Pull the pilot jet and replace it

If that doesn't do it, check your valve clearances

If they are really tight, you probably need a head job, but try re-shimming first

If you have not done a carb service, do this:

 

http://www.dirtrider...r_carb_rebuild/



  • Dasboone

Posted September 14, 2014 - 05:29 AM

#3

Thanks for the tip. I replaced the rings 40 hours ago and re-shimmed the valves to proper specs. I am the 2nd owner and do not believe the carb has ever been gone through. I'm gonna start with the carb. Thx.

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  • FCR Expert

Posted September 14, 2014 - 05:56 AM

#4

I've also seen these symptoms come from a bad/intermittent stator.

If the last valve clearance check was 40 hours ago, I would double check the clearances first. Doesn't take long.

If the valves are good, then pull the carb off the bike and go through it with a fine toothed comb as per the link posted above.

Edited by FCR Expert, September 14, 2014 - 06:02 AM.


  • grayracer513

Posted September 14, 2014 - 09:25 AM

#5

The '07 in particular had stator issues.  Worth checking is whether the bolts holding it to the cover are tight.  They went from three mounting screws to two, and then started having problems with the stator loosening.  The stator tends to develop open circuits within the coils which only show up with heat. 



  • FCR Expert

Posted September 14, 2014 - 01:20 PM

#6

The '07 in particular had stator issues. Worth checking is whether the bolts holding it to the cover are tight. They went from three mounting screws to two, and then started having problems with the stator loosening. The stator tends to develop open circuits within the coils which only show up with heat.


Yup, exactly.

  • Dasboone

Posted September 16, 2014 - 05:57 PM

#7

Good call. I spoke to a Yamaha mechanic who also recommended checking the continuity on the kill switch. I will let you know the results this weekend after I get a chance to work on it again.





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