Major problem with the JD carb kit

I installed the JD kit last week on my WR.. I used the 170 main and recc. needle...The 170 was way to rich and I went back to the 160 main and 48 pilot with Red Needle (85 and high humidity). Now I have a major problem.. the bike pulls so hard in the low to mid my front wheel won't stay on the ground, there is just too much power now.. and Dirt Rider magazine says that too much power is bad ( guess they never figured out how to ride a gear high and lug it) :D Thanks to JD this is the single best improvement I have done, I can't believe the difference :):D I just need to figure out when to go back down to the blue needle.. My bike is a little odd in that it runs alot richer than other WR's...

Like I have been saying the 450's like a leaner main jet than previous WR's but JD's needles are great. I switched down to a 160 main also from the 165 I put in. We are riding together on Sunday so I will get to see your bike rip by me? :)

Jonesy when you finaly bring your bike up here the blue needle is all you well ever need. 3500 ft is about as high as we ride up here and 75 degrees is scorching hot. I agree with you on the JD kit. Best mod I've done so far. :)

Thanks for your feedback on the kit, it is appreciated.

I have been evaluating the '03 YZ/WR carburetors to get to the root of any differences between model years and the fixed main air jet in 2003 appears to be less than a #200(more restrictive). This leads to a smaller main jet, especially when humidity and temperatures rise.

Your results have been noted and I will make an update, specific to the '03 instructions.



I rode Jonesy920's bike this weekend with red needle #4 and 160 main 48 pilot and uncorked stock pipe and it absolutely rips! It feels like it has YZ timing! I just cant get over how well James Dean needle works. I am going to swap my quiet pipe back and forth from the stock uncorked depending on the noise restrictions of where I am riding. Midrange and up his bike smoked mine (left me in the dust). Yes it was loud but the power difference was huge. Thanks again James Dean!

My pleasure,

James :)

Can a carbuerator dummy do this install?

How long will it take?

How much disassembly is required?

If my stock bike runs fine (free mods done, good exhaust), do I need to rejet? Are the gains that significant, or is this just the easiest way to fix your jetting after you tried to get it right on your own, and f-d it up?


Yes you need to re-jet from stock if you have done the free mods. You will not believe the difference in performance, :):D :D the only way you will believe is if you try it :D :D

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