2088 YZ450F motor bogging

6 replies to this topic
  • rider413

Posted April 06, 2010 - 04:58 AM


I have had a 2008 YZ450f since it was new. The bike developed a killer bog while under throttle during the last ride. I pulled the carb and cleaned it. Pulled exhaust pipe. Disconnected the throttle position sensor, and kill switch. I also took the air filter completely off. All of these changes had no effect. The motor will start within one or two kicks. Then rev cleanly to almost 1/2 throttle. Then it falls on it's face so bad it will kill the motor. The jetting is the same as I have run since the last rebuild. Nothing found in the carb. The bike sounds way too rich but removing the air filter has no effect. Has anyone had ignition box or stator problems with these bikes?

  • grayracer513

Posted April 06, 2010 - 08:11 AM


If it's really too rich, you might want to see if the main jet fell out. OTOH, you could be wrong, the bike could be lean due to a blockage in the jet.

  • davbrucas

Posted April 06, 2010 - 01:05 PM


Yup...I was gonna say that its a main jet issue. I would take the carb back apart and recheck. If it isnt that, then its likely electrical.

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  • swatdoc

Posted April 06, 2010 - 06:36 PM


Damn your bike must be trick!!! But how did you get is 78 years early? Time machine?

  • cjxrider125

Posted April 06, 2010 - 08:16 PM


it starts within 1 or 2 kicks, but is it harder to kick over?

  • davbrucas

Posted April 07, 2010 - 05:50 AM


Spark issue...replace stator.

  • Tim1018

Posted April 07, 2010 - 07:56 AM


Damn your bike must be trick!!! But how did you get is 78 years early? Time machine?

And their still using carbs. That disappoints me.

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