O ring mod and stubborn fuel screw

2 replies to this topic
  • BASSic

Posted April 12, 2008 - 06:28 PM


I just did the O ring mod on my YZ426, but I noticed something odd. Even before putting the O ring on, the AP linkage doesn't move very quickly when I chop the throttle. I never had any bog before, but now that the weather is warm I can certainly feel some bog when I chop the throttle.

I installed the heavy O-ring that came with the JD jet kit and even with that, it just stretches until the accelerator pump linkage catches up, and the bog is still present when the throttle is opened abruptly.

After installing the JD jet kit my bike runs great, however there's a little more backfiring and popping on deceleration than normal. I attempted to install an adjustable fuel screw, however I can't get the existing screw to budge. Are there any tips or tricks to get the fuel screw free?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • William1

Posted April 13, 2008 - 03:10 AM


Pull the carb, remove the float bowl. Try a little penetrating oil, work carefully. it is a brass/brass deal so it cannot be frozen, the oring my just have developed a 'set'. The AP rod may have corrosion on it. You need to disassemble the AP system and clean.

  • barbuster400

Posted April 13, 2008 - 12:11 PM


I used the o ring first but mine also stretched. Now I use wire. And like the previous post said, clean the ap rod. My has stuck from not being cleaned enough.

Related Content


First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews

YZ450F 03 Sparks driving me crazy by SirAttard

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

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 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.