engine sputtering..need help


6 replies to this topic
  • sprint4425

Posted June 21, 2008 - 05:48 PM

#1

'03 yz450. new engine, Pro-circuit pipe, zip-ty carb mod. I just plated my bike and i notice that if i am not accelerating and i am in the higher RPM range at a constant throttle position then my bike is sputtering. Have no idea what it is or how to fix it.

anyone know anything about this or know how to fix it?

  • lilyamaharacer9

Posted June 21, 2008 - 05:49 PM

#2

sounds like a jetting issue to me

  • sprint4425

Posted June 21, 2008 - 06:30 PM

#3

sounds like a jetting issue to me


yeah thats what i figured, just dont know how to go about fixing it.

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  • Bombdawg

Posted June 21, 2008 - 08:45 PM

#4

Go back to stock jetting and start from there, never heard of a zip ty mod, what is that?

  • grayracer513

Posted June 21, 2008 - 08:45 PM

#5

How big is your main jet/pilot jet?

  • sprint4425

Posted June 22, 2008 - 07:49 AM

#6

Go back to stock jetting and start from there, never heard of a zip ty mod, what is that?


I am at stock jetting right now, i have never changed it. Zip-Ty mod is a racing modification, do a search for it on here and you should find plenty of info about it.

How big is your main jet/pilot jet?


I havent touched my jetting since i bought the bike, so the jet is still the same size that come stock. I am not really sure what the exact size is off hand, i can look it up if you need me to.

  • grayracer513

Posted June 22, 2008 - 11:46 AM

#7

If the sputtering seems very regular at a steady throttle, try dropping the needle one notch (put the clip higher up on the needle) and/or running the pilot screw a little farther in. If the sputter is irregular, or erratic, and accompanied by the occasional pop in the exhaust at steady throttle, try raising the needle instead.





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