yz450f 07 Hard to start then when warm wont start. need help!

4 replies to this topic
  • That YZ450F Guy

Posted October 21, 2013 - 12:19 PM


I havent started my bike for six months. i drained the bowl when i put her away. I went to start her this am and I had to kick her 20 times just to start her up. then when it warmed up I put it in gear and she died. I could not get the bike to start after that, any thoughts? Thanks for reading!

  • grayracer513

Posted October 21, 2013 - 01:34 PM


Varnish deposit in the pilot jet.  Clean it out.



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  • MotoAce51

Posted October 22, 2013 - 05:27 PM


Check the accelerator pump. My dad's 450 had a bad diaphragm inside that needed to be replaced. Once the new one was installed it started super easy and every time.

  • NitrousR1

Posted October 28, 2013 - 08:04 AM


The accelerator pump is only used on a quick wick of throttle, so the accelerator pump isn't used for starting or idling. The only circuit used for starting and idling is the pilot jet circuit so start there. When u get it started operate the hot start and make sure it is working and releasing fully

  • MotoAce51

Posted October 29, 2013 - 07:17 PM


I only mentioned the accelerator pump because that seemed to help my dads 04. It may have been unrelated but it seemed to help. The issue was that the diaphragm was deteriorating and all cracked/ flaking. The little pieces breaking off we're floating int he carb. I guess it could have been getting in the jets causing the issue. So when we replaced the diaphragm I had to clean the entire carb as well. So I guess I may have fixed one issue while actually trying to fix another. It's just something that found worked.

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