09 450 won't run

5 replies to this topic
  • klogeman

Posted March 31, 2013 - 02:41 PM


Been trying for a couple of weeks to get this bike going. At first it would't even start. I checked the timing and valve clearances and all were good. After cleaning the carb it will start but not run without the choke. it idles fine on the choke and i can snap the throttle with no hesitation. When you shut off the choke it dies. it takes around 10 kicks to get it started. I have cleaned the carb again and it didn't help. I have an adjustable fuel screw with a new o-ring/washer/spring.

I am new to 4 strokes so i may just be not letting the bike warm up long enough. My hour meter/Tach shows around 3k rpm at idle with the choke on. My YZ250 takes less than a minute on the choke.

i've searched the forum for info and a common issue seems to be the fuel screw. I screwed it out 1 1/2 turns when i installed it after cleaning the carb. It probably needs to be adjusted but i really can't do that with it using the choke can I? May be a dumb question but i am used to 2 stroke carbs and they are a little different.

Any ideas? Dirty jets or passages still? I used spray carb cleaner and an air compressor.

  • capt justin

Posted March 31, 2013 - 02:46 PM


start with new pilot jet, that might be your issue, cheap starting point anyway

  • slothman

Posted April 01, 2013 - 01:44 PM


yep the pilot jet is clogged

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  • klogeman

Posted April 02, 2013 - 05:14 PM


Took the carb apart and cleaned it again. Found the Pilot jet plugged again. Thinking some varnish/gum from the pilot circuit passageway plugged the jet. i sprayed carb cleaner and compressed air thru the pilot circuit and was only able to get it out of the pilot air jet on the breather side of the carb. How does the fuel entering the pilot jet get into the carb body? I'm thinking it may be plugged somewhere else. It doesn't make sense for the fuel entering the pilot jet to only go to the pilot air jet.

  • klogeman

Posted April 03, 2013 - 03:58 PM


Never mind, found it. A little more carb cleaner & compressed air and it cleared the passage. Accelerator pump and pilot circuit were both still partially clogged.

  • slothman

Posted April 04, 2013 - 09:46 AM


glad you fixed it :)

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