JD needle vs YZ needle


15 replies to this topic
  • markvfr

Posted April 13, 2008 - 09:19 PM

#1

I searched the archives and could not find an answer. Anyone know if you can compare the YZ adjustable needle to either the Blue or Red JD needle? I'm having some issues jetting right now, and since a lot of the jetting databases here specify the JD needle its hard for me to compare and diagnose. I have the YZ (OBDUS) needle that came extra with my bike.

Thanks.
:thumbsup:

  • 02WR426Cali

Posted April 13, 2008 - 09:21 PM

#2

What year is your bike?

  • markvfr

Posted April 13, 2008 - 09:25 PM

#3

Its in my signature. 2006 WR450.

:thumbsup:

  • old man dan

Posted April 13, 2008 - 09:29 PM

#4

The JD needle is a custom triple taper needle, the YZ needle is similar to the WR needle except that it is adjustable. If you can't get satisfactory performance with the factory or Keihin needles you may want to consider the JD kit, it works great in my WR.

  • markvfr

Posted April 13, 2008 - 09:42 PM

#5

The JD needle is a custom triple taper needle, the YZ needle is similar to the WR needle except that it is adjustable. If you can't get satisfactory performance with the factory or Keihin needles you may want to consider the JD kit, it works great in my WR.


Hmm, I see. So, I can't even compare the clip position between the OBDUS needle and either the red or blue JD needle. Correct?
If yes, that sucks. More trial and error then. :thumbsup:

Thanks.

  • 02WR426Cali

Posted April 13, 2008 - 09:47 PM

#6

I'm sure they are comparable, but it will not be the exact same due to the different tapers. As long as the needles are the same length and the clip positions are in the same location, the only thing that will differ is the taper, so it's semi-comparable.

  • markvfr

Posted April 13, 2008 - 09:55 PM

#7

I'm sure they are comparable, but it will not be the exact same due to the different tapers. As long as the needles are the same length and the clip positions are in the same location, the only thing that will differ is the taper, so it's semi-comparable.


That makes sense. So, can anyone tell me if I should compare for example OBDUS #5 to Red #5 or Blue #5?

THanks.

  • clark4131

Posted April 14, 2008 - 05:27 AM

#8

Because the JD kit is the gold standard around here, 99% of the database cites it in the needle recommendations. James Dean himself checks in regularly on the jetting forum and I'm sure he or Eddie the moderator can give you a definitive answer with regard to comparison...SC

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  • MotoGoalie

Posted April 14, 2008 - 07:30 AM

#9

That makes sense. So, can anyone tell me if I should compare for example OBDUS #5 to Red #5 or Blue #5?

THanks.



Hey dude.

I HAD the YZF needle, i'll need to go home to look at the model number but I can tell you, if you follow the JD kit instruction for altitude and temp the JD needle is FAR superior to the YZF needle as I just went through some problems like this last year.

Im at 6,000 feet and ride up to 12,000 feet all the time with all free mods and a FMF Q.

I'll get my new jetting specs sometime if you want. The only place i differed as I kept my Pilot Jet a little leaner than recommended as it seems people recommend that to be overly rich a lot of times. My bike starts first kick when warm, ALL the time at nearly all altitudes that I listed.

  • markvfr

Posted April 14, 2008 - 09:01 AM

#10

Hey dude.

I HAD the YZF needle, i'll need to go home to look at the model number but I can tell you, if you follow the JD kit instruction for altitude and temp the JD needle is FAR superior to the YZF needle as I just went through some problems like this last year.

Im at 6,000 feet and ride up to 12,000 feet all the time with all free mods and a FMF Q.

I'll get my new jetting specs sometime if you want. The only place i differed as I kept my Pilot Jet a little leaner than recommended as it seems people recommend that to be overly rich a lot of times. My bike starts first kick when warm, ALL the time at nearly all altitudes that I listed.


Hey MG, thanks for the info. Here is a question for ya. Were you having issues with the bike running on the lean side? I ride at 4000-6000' and have a similar setup as yours (all free mods, quickshot2, Twin Air filter, WB E2 slipon). I can't get the friggin decel pop/backfire to stop.

Thanks.

:thumbsup:

  • MotoGoalie

Posted April 14, 2008 - 09:07 AM

#11

Hey MG, thanks for the info. Here is a question for ya. Were you having issues with the bike running on the lean side? I ride at 4000-6000' and have a similar setup as yours (all free mods, quickshot2, Twin Air filter, WB E2 slipon). I can't get the friggin decel pop/backfire to stop.

Thanks.

:thumbsup:


I wasnt getting much decell pop but I had a flat spot in the middle and the power was 'lurchy'. *I believe that's a sign of being lean* Now its butter smooth and STRONG. The JD needle is what I attribute to curing that problem since I changed nothing else.

I'll find those specs tonight and post tomorrow.

{ps, i also made sure my Acell pump was correctly timed as I learned that from owning a YZ450 - that can cause a lot of jetting hassles}

  • William1

Posted April 14, 2008 - 12:38 PM

#12

With a FCR needle, the length is the same for a 38, 38, and a 41 mm carb.

Kehin needles change in taper and diameter only. JD needles are almost always a triple tape design.

Posted Image

  • markvfr

Posted April 14, 2008 - 12:53 PM

#13

I wasnt getting much decell pop but I had a flat spot in the middle and the power was 'lurchy'. *I believe that's a sign of being lean* Now its butter smooth and STRONG. The JD needle is what I attribute to curing that problem since I changed nothing else.

I'll find those specs tonight and post tomorrow.

{ps, i also made sure my Acell pump was correctly timed as I learned that from owning a YZ450 - that can cause a lot of jetting hassles}


Great! Thanks. For reference, could you also tell me what AP timing settings you went with? Did you change the leak jet and did that make any difference? Thanks.

:thumbsup:

  • MotoGoalie

Posted April 15, 2008 - 06:02 AM

#14

mark here ya go;

the needle that came with the AIS is a GDDTR by what i can read. I had it at slot #3.

My current jetting is

PJ 45
Red Needle at #5
MJ 62
FS about 2 out +/-

2006 WR450, 6000 feet, temps around 50'f .

  • markvfr

Posted April 15, 2008 - 06:12 AM

#15

mark here ya go;

the needle that came with the AIS is a GDDTR by what i can read. I had it at slot #3.

My current jetting is

PJ 45
Red Needle at #5
MJ 62
FS about 2 out +/-

2006 WR450, 6000 feet, temps around 50'f .


Excellent. Thanks. So, you didn't change the leak jet or AP timing? Thats good to know.
I caved last night. I'm sooo sick of trying to figure the jetting out, instead of enjoying riding, I ordered the JD kit... we'll see how it does...

:thumbsup:

  • MotoGoalie

Posted April 15, 2008 - 08:33 AM

#16

Excellent. Thanks. So, you didn't change the leak jet or AP timing? Thats good to know.
I caved last night. I'm sooo sick of trying to figure the jetting out, instead of enjoying riding, I ordered the JD kit... we'll see how it does...

:thumbsup:



no changes on leak jet....


Just time the ap according to the manual....or visually TRY and time it to squirt without hitting the slide right off. without setting yourself on fire or getting in your eye:p

I read Sisneros opinion on hardwiring the AP with an oring and he's against it so I left that alone (im concerned it would lead to lower MPG).




 
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