2003 wr 450 big bore jetting

1 reply to this topic
  • wmledger

Posted December 19, 2015 - 04:47 AM


I installed a 478cc big bore kit on my 2003 wr450 and i'm looking for a good starting point on jetting. i'm in northwest ct. at 1040  ft. above sea level with stock exhaust.  thnx

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  • Krannie McKranface

Posted December 19, 2015 - 06:23 AM


A larger bore creates a stronger vacuum at all rpms.

So going SMALLER on the pilot and main is the typical move.

Since you posted no information on the state of tune of your bike and current jetting, there is no way to recommend a specific jetting size.


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