Where is air fuel screw?

8 replies to this topic
  • GreggT

Posted September 15, 2004 - 05:08 PM


I am pretty familiar with mikunis but the 450F carb is a mystery to me.
Where is the air fuel screw, and where do you set it? I know the book says 2 turns out but I can't find it to check it.

  • yzf_rider400

Posted September 15, 2004 - 05:21 PM


it's located on the bottom front (facing towards the front of the bike) of the carb in a recessed hole. It is accessable with the carb on the bike.

  • Fastest1

Posted September 15, 2004 - 05:29 PM


BTW it is a fuel screw, it regulates fuel not air, 2 smoke carbs are just the opposite they regulate air. :thumbsup:

  • GreggT

Posted September 15, 2004 - 05:32 PM


Pointing down? If so I see why Ty sells an extension.

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  • Fastest1

Posted September 15, 2004 - 05:44 PM


Yes, the one pointing down. Kouba makes one too!

  • GreggT

Posted September 15, 2004 - 06:13 PM


Thanks now the questin is what fuel does it regulate and how should I set it. I'm trying to get it to quit stalling in rocky low RPM situations. Also get it to hot start better.

  • yzf_rider400

Posted September 15, 2004 - 06:24 PM


The pilot screw controls the richness of the air-fuel mixture with the throttle closed to 1/8 open. Turning in leans, turning out richens.

To keep it from stalling in low RPM conditions either set your idle higher or adjust the pilot screw for the optimum conditions you're riding at the time. Possibly more cluctch control and/or a flywheel weight.

Others could provide much more information than myself. I would also check out the jetting forum as well and use the search function to find previous threads. Much of this has been talked about before.

Good luck! :thumbsup:

  • Fastest1

Posted September 15, 2004 - 10:15 PM


I would agree, I would also get the JD Kit. I have heard nothing but rave reviews on his tuning products. Never hesitate to ask a question here, it is hard to look up things sometimes. :thumbsup:

  • ovrrdrive

Posted September 16, 2004 - 01:22 AM


Everything you ever wanted to know about the fuel screw is here: http://www.atlanticm.../00000135.shtml


Go ahead and splurge and get a zipty fuel screw. Even after you get yours adjusted right, it needs fine tuning every time the weather changes. The zipty, or any other brand of extended fuel screw, makes that easy.

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