Yes !!! ANOTHER jetting question.

5 replies to this topic
  • BSF-N-Colo

Posted August 21, 2001 - 02:24 PM


And YES, I have searched the site for what I'm lookin' for but haven't found exactly what I need.

My jetting is good from about 1/2 to full throttle, but I would like to have the front come up a little easier/quicker in the lower gears, for those known (and unknown) obstacles we all love. I also still have the "Yamabog" problem, when I crack it open quickly.

This is my current jetting specs:

'00 WR400F

DRS clip @ #5
MJ #160
PJ #40
PAJ #75
MAJ #200
fuel screw 1.5 turns out
Air box cover gone
Stock pipe w/o baffle
Haven't done anything with the pumper yet

I am probably going to a 52 tooth rear sprocket soon , so I think that will help some.

Can anyone, especially you CO boys, recommend something here. I'm suspecting I need a different needle, but am confused as to which one. Also, I'm not planning on going to the YZ timing just yet. Is the "BK Mod" still recommended ?.


  • Red_Beard

Posted August 21, 2001 - 02:59 PM


Have you done the grey wire mod and what does your spark plug look like. I have an 01 wr w/yz timing stock needle in #2 pos with a #175m and a #45p, grey wire mod and air box lid off, stock pipe w/silencer out and my bike runs really nice. My alt is 3500 to 6000 ft. I to have changed my gear ratio by dropping one in the front and adding one in the back. Love it for tight mountain riding.

  • John_in_Long_Beach

Posted August 21, 2001 - 05:31 PM


The problem is the DRS needle.

Get rid of it. The "E" series needle comes on much quicker. I found the DRS needle to be too mellow. The DRS feels quick right off idle, dead between 1/4 - 1/2 throttle, then it starts to work again.

The E needle will absolutely solve your problem. The change will make the front end come up much quicker.

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  • BSF-N-Colo

Posted August 22, 2001 - 09:36 PM


Thanks for the info John, I had the EK* in mind when I wrote the orig post.

Which needle would you recommend for semi-high altitude (5000'-8000')?. And will it work the same for WR timing vs. YZ timing ?.

I have found a very good FCR tuning desciption here Including a needle chart. This probably isn't new to most of you though :)

  • John_in_Long_Beach

Posted August 22, 2001 - 03:27 PM



I have the EKN needle in my bike, this was recommended by James Dean over the EKP for my set up. Yes, I think that the YZ timing is more appropriate for the E needle. But you would want this anyway for a better ability to lift the front end.

Most of this is from memory, the bike runs so well I never have to mess with the jetting.

2000 Model, YZ timing, throttle stop chopped, no air box lid, DSP tapered header and pipe, 172 main, 200 main air jet drilled to 226, and bore for MAJ passage drilled to 278, 100 PAJ, 48 pilot jet. EKN #4 position.

Now if memory serves me correct, the last number "N" in the EKN is for the straight bore of the needle, the N should be smaller than the P therefore it will plug the hole less and make the bike run richer on the lower end until in comes on the tapered section.

Maybe James recommended this for me since I was running a very free flowing exhaust and only up to 5000 feet.

My bike runs flawlessly from 0-5000ft. For you maybe the EKP should be the way to go. Go to YZ timing with the needle change. You won't be disappointed.


  • BSF-N-Colo

Posted August 22, 2001 - 05:38 PM


Thanks again John. I see that I can get EL*
series needles from Riva Yamaha, which I believe are just a half clip leaner than the EK* series.

Anyway, thanks for the input.


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