YZ426f Backfiring on de-acceleration


11 replies to this topic
  • YamahaYZ426F

Posted April 19, 2007 - 03:55 PM

#1

I got a 2001 yz426f and on de-acceleration it back fires any advice on how to fix the problem thankss guysss.

  • buzzgrizz

Posted April 19, 2007 - 04:11 PM

#2

mine does the same thing put some gasket sealer on the area where the head and mid pipe slip together it will help some.

  • 133_Bradley

Posted April 19, 2007 - 04:41 PM

#3

try playing with the fuel screw a little and see if that helps.

  • 642MX

Posted April 19, 2007 - 06:08 PM

#4

2 things. An exhaust leak or its too lean. If the exhaust system hasn't been touched, then turn your fuel screw out a little bit.

  • grayracer513

Posted April 19, 2007 - 07:45 PM

#5

Pretty much what he said:

http://www.thumperta...599#post3710599

  • YamahaYZ426F

Posted April 20, 2007 - 11:48 AM

#6

Thanks for the help:thumbsup:

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  • creeker

Posted April 20, 2007 - 04:53 PM

#7

My 00' 426 does the same thing... Just replaced the midpipe muffler gasket and it is still popping. Fuel Screw is 2 turns out. Is it possible to have an exhaust leak where the header comes out of the motor?

  • xrmarty

Posted April 20, 2007 - 04:58 PM

#8

How much backfiring are we talking about? Because, some popping on deceleration is fine and expected, but if it sounds like cannons going off than you might go over your jetting.

  • creeker

Posted April 20, 2007 - 05:00 PM

#9

How much backfiring are we talking about? Because, some popping deceleration is fine and expected.


Not a whole lot... maybe it is just normal with mine at least. Thanks!

  • 642MX

Posted April 20, 2007 - 05:45 PM

#10

Is it possible to have an exhaust leak where the header comes out of the motor?


Anything is possible.

  • 642MX

Posted April 20, 2007 - 05:47 PM

#11

How much backfiring are we talking about? Because, some popping on deceleration is fine and expected, but if it sounds like cannons going off than you might go over your jetting.


^^^ Correct. YZF's will pop just a little, even when properly tuned.

  • felix 222

Posted April 20, 2007 - 07:52 PM

#12

you're running the bike too lean...simple and easy fix





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