2009 yz450f problem

8 replies to this topic
  • Themackattack

Posted May 26, 2011 - 02:53 PM


I just bought this bike 3 weeks ago and noticed that it pops alot when slowing down threw every gear. I was wondering if i can change some jets to make it run a little smoother?

This is my first bike so i would like to get it running top notch.

Thanks everyone

  • grayracer513

Posted May 26, 2011 - 03:07 PM



  • richardnoggin

Posted May 26, 2011 - 03:09 PM


i own the same bike and it has always popped when downshifting and slowing down,i have tryed jetting and still pops,i have rode this bike for 2 years and did not touch anything and when i decided to change piston and rings and valves i did not have to because everything was in specs,great bike and enjoy the best year bike yami ever put out!

  • Themackattack

Posted May 26, 2011 - 04:31 PM


The link as for a 2006?

I forgot to add i also have an fmf pipe with megabomb header on it. I also have the red fuel screw on it

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  • dvn

Posted May 26, 2011 - 06:35 PM


The link is for a 2006?

I forgot to add i also have an fmf pipe with megabomb header on it. I also have the red fuel screw on it

It still applies. Read the sticky on adjusting your fuel screw.

  • Themackattack

Posted May 27, 2011 - 05:42 PM


what is an fcr carb and an a cv carb?

  • grayracer513

Posted May 28, 2011 - 08:52 AM


The Keihin FCR-MX is the carb the '03-'09 450's came with. Slide throttle with an accelerator pump. "CV" carbs (constant velocity) often come on quads, and have a manually opened butterfly throttle valve with a slide throttle in front of that, operated by intake vacuum so the throttle is actually opened by the engine's demand for air.

Why do you ask?

  • Themackattack

Posted May 28, 2011 - 12:17 PM


On the link you sent me he mentions an fcr carb and a cv carb

just wanted to clarify what one i had

  • Themackattack

Posted June 07, 2011 - 03:18 PM


alright i checked with my fuel screw and i had to turn it like 3.5 turns out to get it to run smooth, So ill be trying 1 size bigger on my pilot jet to see if that helps!

Thanks guys

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