yz426 jetting

3 replies to this topic
  • 01_426f

Posted October 04, 2007 - 08:10 PM


what altitude are stock bikes jetted for?

  • 426 NOOB

Posted October 05, 2007 - 11:23 AM


According to http://motoman393.th.../426jetting.xls about sea level depending on temp. of air.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted October 05, 2007 - 12:51 PM


As lean as most of them have been lately, I'd guess 2500-3000 feet, but I don't know what the actual target altitude is supposed to have been. I run the 165 main jet that my '06's were delivered with at altitudes running from sea level to 3500 feet with no real problem, but I did bump the pilots up a notch.

  • SRT426

Posted October 05, 2007 - 10:26 PM


The 426 comes jetted for Sea Level at 70 degrees. Be sure to use Motoman's jetting chart as shown in the posts above, it will get you real close to where you need to be.

Related Content


James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

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

YZ450F 03 Sparks driving me crazy by SirAttard

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

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

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.