03 yz450f jetting

1 reply to this topic
  • moorespeed426

Posted September 14, 2004 - 09:21 PM


I recently bought a 03 yzf450 and finally checked the plug, it is dark black{rich condition}, the jetting in the carb is 162 main, 42 pilot, needle 4th pos]. Stock is 165mj, 45p, needle 4th. I had a 2000 yz426f before this bike and did the BK Mod and it worked great. Have as anyone messed with the timing or duration of the pump on the 450's, as my bike has leaner than stock jetting I believe the pump is causing the rich condition. Thanks

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  • Ga426owner

Posted September 15, 2004 - 07:26 AM


No BK mod necessary - I did adj duration screw - 1/4 turn and I went with JD Jetting kit and I am extremely happy.... There are different diaphrams available for even more tweaking adjustments: see link below



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