Help!!! Need help finding a pilot jet!! ASAP

Just came back from riding in the mountains of Colorado (Rampart Range). Had a great time, but can't get any low end power out of my bike. From the posting on this site about altitude jetting I am needing to drop to a 42 pilot jet, but I have spoken to three dealers and they give me a standard Keihn Pilot jet and my WR takes some strange jet. The pilot jet I pulled out is a 45 and looks more like a Mukuni (sp?) than a Keihn. What's up with this?

Am I loosing my mind?

Is this a rare jet?

Why am I having so much trouble getting the correct jet?

I would appreciate any help. I leave tomorrow for Colorado (Gunnison area)and desperatly need to get my jetting correct.

Doug Kuntz

Kansas (105 degree weather lately)

98 WR400

Stock Pipe and header - no baffle

Stck Air Cleaner

Top of airbox removed

WR timing

I’m not a doctor, but from a mental health perspective I think you check out fine.

Anyway, no, the Keihin Slant FCR doesn’t use the same pilot jets as “normal” Keihin carbs. These jets are not rare, but unfortunately intelligent dealers are.

You may also try dropping your needle a clip or two.


Thought I was loosing my mind or something. Thanks for the help and yes I have already moved my clip to the #2 position.

Kansas Settings:

Main 170

Pilot 45

Clip #4

Fuel Screw = 2 turns out

Colorado Settings tring to achieve.

Main 162

Pilot 42

Clip #2

Fule Screw = 1 3/4 turn out.

Thanks a lot!!

Try turning in the pilot screw in more, 1-1 1/2 turns. Then have your Yamaha dealer look up the part number for the '98/'99 WR pilot jet or call Sudco and be sure to get their FCR version of pilot jet.(1-800-998-3529)


Glad to see you still check up on us from time to time. Thanks, and don’t be a stranger.

i had same problem.i went to 3 different dealers when i showed them pilot jet they acted like it was a part from outerspace.none of them could find it on there computer or even had any idea where i could purchase a similar pilot of them even said "it couldnt be from stock wr400 maybe someone put a jetski carb on my bike".i havent been back to that dealer since.i ended up ordering the correct jet from dennis kirk.

You could also order the jet from Yamaha. Here are the Yamaha Part numbers for and prices from


<LI>3TJ-14948-05-00 STD JET (#45) $8.40

<LI>3TJ-14948-03-00 ...JET (#40) $12.51

<LI>3TJ-14948-04-00 ...JET (#42) $8.40

<LI>3TJ-14948-06-00 ...JET (#48) $8.40

<LI>3TJ-14948-07-00 ...JET (#50) $8.71

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