JD needles

This info is very interesting since everybody says nothing but good words for the JD.

I have spent a lot of time with the needles and jets on my '03 WR. recently i bought a Factory Pro carb kit but i am not happy with it. The bike won't run smooth and it sputters.

Now i just ordered the JD Jetting Kit and i am very curious to see the results...

This info is very interesting since everybody says nothing but good words for the JD.

I have spent a lot of time with the needles and jets on my '03 WR. recently i bought a Factory Pro carb kit but i am not happy with it. The bike won't run smooth and it sputters.

Now i just ordered the JD Jetting Kit and i am very curious to see the results...

did you try the adjustable YZ needle yet?

I had one of the adjustable, yz needles and changed it with the red JD needle, clip 4th from the top, and the bike pick up mid and top end, no complants here, no jet change. I run a 160, at 10,000ft.

I had one of the adjustable, yz needles and changed it with the red JD needle, clip 4th from the top, and the bike pick up mid and top end, no complants here, no jet change. I run a 160, at 10,000ft.

That was one of my gripes was the bottom end. The leak jet helped that but still had a slight hesitation. tried every setting and main to get rid of that. The surge was horrible with the JD's and never went away until I got the YZ. Now zero surge. I'm posting from my experience with JD's and my wr450. I'll admit, I'm no expert but, I ain't no dummy.

I still have bog issue due to the AP on tite trails, need a fix for that but the R & D AP is $250.00.

I still have bog issue due to the AP on tite trails, need a fix for that but the R & D AP is $250.00.

I haver a Boisen quickshot2 to and I put ina larger leak jet. that made a big difference. I never completely got rid of it till I put in the YZ needle.

did you try the adjustable YZ needle yet?

I haven't tried the stock YZ needle. I tried though a slightly richer needle,for FCR's, and the bog dissapeared. But i lost power comparing with the Factory Pro needle. I don't know, i guess i should try the YZ needle:confused:

I haven't tried the stock YZ needle. I tried though a slightly richer needle,for FCR's, and the bog dissapeared. But i lost power comparing with the Factory Pro needle. I don't know, i guess i should try the YZ needle:confused:

It's cheeper to try the YZ needle first is all I'm saying. If it still isn't to your liking you can spend bigger money. cheaper to try the YZ first:excuseme:

It's cheeper to try the YZ needle first is all I'm saying. If it still isn't to your liking you can spend bigger money. cheaper to try the YZ first:excuseme:

Well the problem is that i have already ordered the JD kit. I read everyone saying the best for JD, so it never crossed my mind to try the YZ needle first...

Hope that the kit will work and not cry for my money.

thanks for the info though Charles! At least i know what to do next if i still have problems:thumbsup:

Charles, are you using the STD YZ needle or one of different YZ options for the higher altitude? What's your final set-up with jets, clip, TPS, CDI, etc.?

Charles, are you using the STD YZ needle or one of different YZ options for the higher altitude? What's your final set-up with jets, clip, TPS, CDI, etc.?

Yes I'm using the standard. needle. I have my set up posted in the jetting data base

Just looking at your specs, Why does a 450 require a 158 main jet at 5,000 to 9,000 ft. I run a 426 at 9,000 to 10,000 ft with a 160. just wondering:confused:

Just looking at your specs, Why does a 450 require a 158 main jet at 5,000 to 9,000 ft. I run a 426 at 9,000 to 10,000 ft with a 160. just wondering:confused:

The bike ran too rich with the 160 in it when I ran it:excuseme: 158 is stock:prof:

That was one of my gripes was the bottom end. The leak jet helped that but still had a slight hesitation. tried every setting and main to get rid of that. The surge was horrible with the JD's and never went away until I got the YZ. Now zero surge. I'm posting from my experience with JD's and my wr450. I'll admit, I'm no expert but, I ain't no dummy.

The comment above doesn't make sense if you understand the differences between the needles.

There should not have been any surging from the jet kit needles and the Red needle should have worked perfectly. You could have had some other effects from ignition or a clogging problem somewhere else. The jet kit's Red needle will not be too rich and won't surge if used in the 4th or 5th from top clip position. You might have needed to adjust the fuel screw further than expected, especially with aftermarket fuel screws. The dimensional tolerances on many of the aftermarket fuel screws are not close to the factory fuel screw, which makes tuning the fuel screw unpredictable.

With any of our kits, if you aren't satisfied, return the kit for a full refund. I believe there was another issue going on in this case.

Thanks,

James

The comment above doesn't make sense if you understand the differences between the needles.

There should not have been any surging from the jet kit needles and the Red needle should have worked perfectly. You could have had some other effects from ignition or a clogging problem somewhere else. The jet kit's Red needle will not be too rich and won't surge if used in the 4th or 5th from top clip position. You might have needed to adjust the fuel screw further than expected, especially with aftermarket fuel screws. The dimensional tolerances on many of the aftermarket fuel screws are not close to the factory fuel screw, which makes tuning the fuel screw unpredictable.

With any of our kits, if you aren't satisfied, return the kit for a full refund. I believe there was another issue going on in this case.

Thanks,

James

I ran 4th and 5th clip several different times. each time with different main jets and leak jets. I never had the surge before the jd needles and haven't since removing them. I rode the bike to work today and no surge what so ever. :worthy: The main reason I quit using them is they didn't fair well when there were big altitude changes. Sometimes riding lower,, sometimes riding higher the bike ran well with a very small range. Outside that range it didn't run that well or start that well or it bogged. Over the same trails the YZ needles seems to have a broader range. I just found myself always fussing with the red needle. Tired of that. I prefer to ride more than wrench. JD I'll keep the Kit. No sweat. Maybe I will change my mind someday. If your ever in Bozeman MT. give me a heads up and you can certainly give it a look.:thumbsup:

I've had really good luck with the JD needles in my WR250 and any questions I had about them were answered promptly and courtesly.

But I had better results with a 15 dollar YZ needle.

The bike ran too rich with the 160 in it when I ran it:excuseme: 158 is stock:prof:

Stock is 165

The JDJetting kit needles in Yamahas need a much bigger main jet than stock. The larger tip of the kit needle affects fuel flow at full throttle, reducing flow, so there needs to be an increased main jet size or results will be less than ideal. The kit's needles are also tuned at each increment of throttle position with added tapers and specific taper lengths to make a better air/fuel mixture in each throttle range. If there were a stutter from jetting, then the needle clip was probably too rich because there should be less sensitivity to elevation changes with the needle profiles refined to this level.

I also want to mention that WR's commonly have ignition stutter with perfect jetting mixture at low throttle range -and- steady riding. This is NOT jetting, but ignition mapping that goes away when opening the throttle more. The issue is cured with an ignition change, but can be misinterpreted as poor jetting.

See- http://www.pbase.com/jdjetting1/wr450f&page=2

-and below-

99388111.jpg

It could be that Red #3 was needed with a bigger pilot jet. I'm always looking to help if anyone needs improvement with the kit. Please feel free to email me if needed.

Thanks,

James

JDJetting@comcast.net

Stock is 165

Mine came with a 158. ( I remember clearly looking at the book and the jet and scratching my head) Book says 165:excuseme: The wife is gone this weekend and I'm going to play around with it more. This will be the last time I mess with the jetting. I'll put the red back in and run it with the biggest jet I have. The last time I did this it was hard to start and didn't run very well. I'll size down from there. I'm a shadetree mechanic and willing to try the advice. I still have a feeling that I will end up with the YZ. But since James Dean himself has chimed in I will give it one more shot. I really feel like if I have to rebuild the carburetor to run the JD kit it's not worth the fuss to me. The kit should come with leak jets, pilot jets and fuel screw. I did not have success with just replacing things that came in the kit. Believe me when I first installed the JD kit I tried red needle, blue needle every jet that came in the kit. The JD kit ran better than the stock set up with the red needle 5th position and 160 main. It ran best this way. It did not kick start very well and took quite a bit from the starter. I had bog and surge. Since removing them I have not had those issues. As I said I'll give it another shot:thumbsup: this is it though:prof:

Charles, I just got my '08 back from the dyno yesterday. This bike is now a missile! Starts instantly, NO STUTTER AT ALL, no front tire on the asphalt through ALL the gears, no overheating, etc. For the first time since I bought this bike it was close to scarring me last night!

In another post I had worked the stutter down to cam timing or jetting. It's ALL jetting. I know JD has shown some ignition spikes in his tests, but in the end IT WAS THE JETTING on my bike.

I'm at 5300' and my main jet is now a #152, "mystery needle" from the GYTR-AIS removal kit is now on 2nd from the top, OEM main air jet is 2.0, and all else in the carb is OEM stock. I'll try to head for higher ground this weekend and see how she does, but right now it's really tough to hold on to!:thumbsup:

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