Jetting help

3 replies to this topic
  • Parx_400

Posted September 17, 2009 - 01:03 PM


Hi Everyone,

I have a 2005 WR450. I am running the JD jetting kit and followed the instrutions for sea level. (170 main, stock pilot, red Ni at 3rd or 4th clip. The bike runs good on the top end but seems like its bogged down at the lower RPM's. If i lug the bike crusing on the street it seems like its getting loaded up and will die when i come to a stop. If I'm hammering the bike and come to a stop its fine. The bike has the folling mods:

Drd full pipe,
Smog thing removed.
Airbove has the snorcal out, the hodler for thesnorcal cut out, and the side cut out in the 2 locations.
WR exhauset cam (Changing to YZ in a week).

I have the fuel screw out 1,1/4 turns.

What should I trying to correct this?

  • arctic954

Posted September 17, 2009 - 06:21 PM

#2 over simplify a complicated thing.....

Full throttle is your Main jet...... Mid throttle is the needle. Idle to mid.... is your fuel/idle screw. If you wack it from idle --- it could either be the fuel/idle settings or the accel. pump setting.

I'd start by putting you bike on a stand......starting it and setting the idle to a good RPM..... then start experimenting with the fuel screw....

Turn it in 1/2 turn.....blip the throttle.
Turn it back a 1/2 turn....blip the throttle.

Keep experimenting.....if the bike increases its idle (it will sound like its running better all of a sudden....wait a sec. then reset the idle RPM back to where it sounds normal....)

You will find the idle/fuel screw sweet spot. If you don't --- you probably have the wrong idle jet.

Or...... your idle jet is clogged.

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  • vfr661

Posted September 19, 2009 - 08:48 PM


According to the instruction I got with my JD kit for the WR450, you should be using the BLUE needle. You might want to check the instruction that came with your JD kit.

  • Krannie McKranface

Posted September 19, 2009 - 08:50 PM


Yes, Blue for sea level, 3rd clip.


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