Carb adjustment help please???

3 replies to this topic
  • bnyfe

Posted March 14, 2010 - 03:40 PM


Just got rid of a 2008 450F and had it dialed in perfectly for my elevation 100' and ambient temperature.

Just bought a brand new 2007 450f off a guy who bought it, rode for like 5 minutes, scared himself and parked it for the last 3 years.

I completely disassembled the carb, cleaned it, and put it all back together. This is my first time doing a 4 stroke carb, but I know that it is back together properly. I followed the manual and triple checked everything.

I have all the stock jets in there and the pilot screw is set to 1.5 turns out. When I wick the throttle on with no load, the motor hesitates and then comes on.

The air filter barely has any oil on it, as the oil that is there is still the stuff from the factory and it's three years old and barely existent.

Any ideas to help me?

Thank you.:banana:

  • ForsheeMS

Posted March 15, 2010 - 08:46 AM


You really need to jet the bike by riding it. Sitting on the stand and stabbing the throttle will most likely result in an off idle hesitation or bog no matter what. Try riding the bike and see what it does and adjust it from there.

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  • grayracer513

Posted March 15, 2010 - 08:57 AM


This is true. At in neutral, the timing is remapped, and underway, you rarely open the throttle quickly from speeds as low as an idle.

Nonetheless, verify that your accelerator pump is working, and that it's timed correctly (see the manual). You may also want to revisit the pilot jet to be certain that the cross holes are clear and that the idle discharge port is open and clear. Look in Common Threads for posts on pilot adjustment, jetting, etc.

  • bnyfe

Posted March 16, 2010 - 07:37 PM


Ok...thanks guys...will do the same...

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