How to determine if aftermarket jetting has been done??

6 replies to this topic
  • billykidd2000

Posted May 04, 2006 - 02:16 PM


I just purchased a 2000 WR400F and I wanted to buy a JD Jetting kit but I'm not sure if there is already some aftermarket jetting done.

What's the best way to tell if it's been done? :crazy:

  • dbailey223

Posted May 04, 2006 - 02:33 PM


Only way I can think of is to actually yank the jets and needle from the carb and see if the jets (numbers printed on them) match the stock settings and see if the needle is the stock one. The JD kit, at least mine, included a red colored needle and blue colored needle.

  • billykidd2000

Posted May 04, 2006 - 02:44 PM


Any idea what the stock jetting numbers are?

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  • dbailey223

Posted May 04, 2006 - 02:57 PM


My only experience is with an 03 wr 450, which I believe from memory is 45 on the pilot jet, 70 on the leak jet, and 160? something on the main jet. If you have the parts manual or can download it, I think you can find it there--but just a guess.

  • Numskull

Posted May 04, 2006 - 05:47 PM


here is the break down for the 2001, im not sure if its the same as the 2000 cause there were alot of changes. http://oem.thumperta...carburetor.aspx

scroll down to the parts list and you will see the standard jets along with the opptional. You will have to pull your float bowl off to pull your jets and check the numbers on them.

Why are you jetting?

  • rich1167

Posted May 04, 2006 - 06:25 PM


Go to Yamaha's web site. Their is a parts section where you can look up all the info you need. 165 is the stock main and 45 is the stock pilot according to their info.

  • billykidd2000

Posted May 04, 2006 - 08:36 PM


Thanks for the help!


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