Air Screw on 450

2 replies to this topic
  • Jetsprint2

Posted June 29, 2005 - 12:03 PM


My bike is running great and my 04' 450 is my first four stroke. I do all of the right maintanence and have owned the bike for a year now. From the time that I picked the bike up from the dealership I have not had to adjust anything. What I want to know is when you should adjust the airscrew if needed. Can you tell by how the bike idles? Just looking for some input thanx. :)

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • SureBlue

Posted June 29, 2005 - 12:28 PM


Your Keihin airscrew is in fact a fuelscrew since it sits between the cylinder and carb slide (= on front of the slide) on the bottom of the carb. Opening it up counterclockwise gives it more fuel. You can open it up half a turn for every winter, because colder air contains more oxygen which may make it run too lean without more fuel.
When the weather is very warm or humid you could close the fuel screw a bit, but I would not go leaner at all if the bike has run well so far. A bit too much fuel is never bad. If you want to do something, try opening up 1/4 turn and see if it runs even better now. If it runs like before, don't go back.

  • SureBlue

Posted June 29, 2005 - 02:13 PM



Related Content


Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

YZ450F 03 Sparks driving me crazy by SirAttard

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.