WR450.... flat spot in the mid range

10 replies to this topic
  • xr600r

Posted April 10, 2004 - 03:15 PM


my 450 has great bottom and top end, but seems to have a flat dull spot in the mid-range. i'm running the JD jeting kit...gyt pipe insert, and the airbox has been opened up.
any suggestions ?

  • MN_Kevin

Posted April 10, 2004 - 04:34 PM


1 - disconnect your gray wire

2 - disconnect your TPS

3 - Disconnect both

  • xr600r

Posted April 10, 2004 - 04:50 PM


The grey wire was disconnected before i ever rode the bike.
disconnect the Throttle Position Sensor ?????? give me some more insight on that one, if you could please. :)

  • mike73

Posted April 10, 2004 - 05:29 PM


i have same bike with same problem. i installed the jd kit, and am currently working with clip position to see if i correct it. so far i have been unsuccessfull. i PM'd JD with questions, if i get this worked out, i'll let you know. i'm running the blue needle, clip is now in 1'st position. i tried 2'nd, 3'd fourth.... same problem.

  • mtrablue

Posted April 10, 2004 - 05:33 PM


don't be to quick to disconnect the t.p.s. it sounds like you need to get some jetting straightened out. you've got the jd kit but you didn't say what you jetting is right now. red needle, blue needle, clip position...... let us know what your current specs are.

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  • Indy_WR450

Posted April 10, 2004 - 05:51 PM


You need to be on a 165 main and red #5 in Michigan with 60 degree weather. :)

  • xr600r

Posted April 10, 2004 - 06:30 PM


i rode today...40 out. blue needle #4

  • Indy_WR450

Posted April 11, 2004 - 02:24 AM


165 main and blue #4 is right on for 40 degree weather. What is causing mid range jetting issues? :)

  • xr600r

Posted April 11, 2004 - 03:37 AM


Is it even a jetting issue ? :) i dont know. as was said earlier, i'm not the only one with this problem. it runs ok in the mid range..it just seems to kind of flatten out until she's screaming on the top end. :D

  • mtrablue

Posted April 11, 2004 - 04:03 AM


that's a good point. rider to rider, bike to bike. what you feel is a flat spot, i might not even notice when i ride. is it a bog type feeling? do any of your buddies have wr's? have you ridden theirs? a lot of us run exhaust inserts because their only about fourty bucks and are a big improvement over stock, but would a fmfQ (or p.c., white bros. .....)be what we really need for these bikes?

  • MN_Kevin

Posted April 11, 2004 - 07:19 AM




Disconnect it, try it. If it is better...GREAT! If it is the same...hey you gave it a shot. This whole evolution will take less than 5 minutes.

As for going after your jetting first...let's see, one takes 30 seconds, the other a day of testing.

hmmm... :)


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