Emergency help needed.


4 replies to this topic
  • hawkins1

Posted March 19, 2004 - 08:15 AM

#1

I just installed a fmf titanium pipe and mid pipe. I am getting a ton of back fire do I need to loosen the fuel screw on the bottom of the carb or re-jet it. 01 yz 426

  • BrandonW

Posted March 19, 2004 - 08:19 AM

#2

Turn the fuel screw out, to a max of 2 turns. If that does not make the backfire subside, then your pilot jet needs to be changed to the next bigger size, and redeaux.

:)

(New pipe is allowing it to breath much easier, and I bet your air/fuel ratio is a little on the lean side. Good luck!)

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  • Indy_WR450

Posted March 19, 2004 - 10:50 AM

#3

Most likely need to raise your needle. Dont mess with your pilot until you get the needle closer. :)

  • WR450F_RDR

Posted March 19, 2004 - 01:12 PM

#4

I second Indy's thought, raise needle first, maybe even go to a larger main jet? ( you dont list your current jetting settings?)

  • Treebark

Posted March 24, 2004 - 05:22 AM

#5

The fuel screw will only effect idle and off idle fuel air mix and would change the main jet to a 170 or 175. I put a stock yz muffler on and had to change main to a 175 and that took care of it. The needle may need to be raised if your having a throttle response problem such as having a hessitation. My 04wr450 expierenced the same problem after I changed my exhaust and Raised it one notch to (#5).




 
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