Page 1 of 1
JD Jetting Anyone tried these on their KDX?
Posted: 07:42 pm Dec 20 2009
by frankenschwinn
Posted: 08:17 pm Dec 20 2009
by Indawoods
Got 'em... haven't tried them yet. Like my DEK pretty good....
Posted: 12:41 am Dec 21 2009
by canyncarvr
I want my frankenschwinn daddy to buy me JD's set for Christmas!
You can keep the jets...I gots lots'a those..... I just want the Christmas Needles..
RED 'n
GREEN!!
Ah, never mind. I've always wanted to try out one of his needles. They aren't cheap..but JD was a main force behind getting the RB-modified carb to work as well as it does all those years ago. I'll gladly buy a needle or two from him.
I didn't think I could count on FrankenSchwinn...so SANTA is going to bring me a couple!!
Merry Christmas to me!!
Posted: 08:38 am Dec 21 2009
by frankenschwinn


canyncarvr wrote:
I didn't think I could count on FrankenSchwinn...so SANTA is going to bring me a couple!!
Merry Christmas to me!!
A wise man indeed...
Posted: 11:50 am Dec 21 2009
by canyncarvr
There are a couple of guys that run JD's needle. Don't recall offhand who they be.
I'd asked JD about his needles..for a profile to put them into his jetting guide spreadsheet (you know of that?). Of course...he doesn't release that information.
He did give me some 'close to' for comparison purposes...but there has been some hack-n-slay trimming of email-boxes on this machine...I guess he was a victim of death-by-deletion.
Well...la-de-da. I found it here!!!
JD wrote:
The needles in the KDX jet kits are in the same range as CEK/DEK single taper needles, but ours are custom machined triple tapered needles. They are precision machined and give a more even flow of power than standard needles, but do not get excessively rich like N85D type needles. There are 2 needles in the kit, which span either side of CEK/DEK with slightly richer and slightly leaner straight diameters. The Blue marked needle is for lower elevations and cooler temperatures (richer), and the Red marked needle is leaner on the straight diameter for warmer conditions or slower paced riding, but not excessively. Yes, these are special needles, as I've spent years developing and refining the taper angles and lengths to make them perform in varied conditions without being as sensitive to changing weather and temperatures compared to stock needles. The needles will work well with the RB modified carburetors.
The main jets included are standard Keihin hex type, with 4 included in the KDX200 kit (#150-#165 by 5's). We can add main jets of other sizes if needed.
Thanks,
James
From
HERE!
poop. I couldn't remember if they were red/blue or red/green. His site didn't say. So..shoot me for the
red,
green comment.........
I did wonder at the time about the 'by 5s' comment, 'cuz Keihin jets are not 'by 5s'. Well...if you skip a size they are. Skipping jet sizes seemed strange coming from a jetting expert.
What do I know. I just ride what I like.

Posted: 12:05 pm Dec 21 2009
by Mr. Wibbens
>|QBB<[/url]
canyncarvr wrote: So..shoot me for the red, green comment.........
ok,

Posted: 12:58 pm Dec 21 2009
by canyncarvr
Mr. Schwinn: DO follow the link in my last post. ..click on 'HERE! up there.
You're looking for input on use of JD's needles in the KDX. That link will be helpful.
Posted: 12:59 pm Dec 21 2009
by RBD
but JD was a main force behind getting the RB-modified carb to work as well as it does all those years ago.
This is some wrong information "CC". JD did not help me with my carb modification and he had no hand in it at all.
Shortly after getting my mod up and running so to speak, I did get a call from James asking about doing some divider plates in a bunch of PWM carbs he had and was trying to set them up for the KTM's with the short body PWK's
I think I did one or two of them for him, He was kind of wanting me to handle his jet kits and he would send the carb and customer to me for the mod and his jet kit. That really did not materialize.
I have had conversations with him over the years and he did tell me once that he was out riding and ran across some guys riding KDX's (200 or 220 can't remember) one of them had my carb mod. They kind of hooked up for the day and they tried one of James needles in the KDX.
James told me he thought it worked well and with a little fine tuning on the jetting he thought it would be a great set up.
Happy Holidays,
Ron
Posted: 03:27 pm Dec 21 2009
by canyncarvr
Ron: I didn't say he helped you with the modification. I know he had no hand in your modification of the carb at all.
His input was more of a generic carb-tuning 'how-to'. I have 62 pages of printed material that started with 'RB Designs Jetting Info Needed' in which JD was very helpful. I have used his jetting spreadsheet many times to 'see' jetting choices before trying them...or deciding NOT to 'cuz they weren't what I was after. That is indeed being a 'main force' behind getting my bike to where it is today.
Please...'getting to work as well as it does' (what I said) has nothing to do with 'helping' with the modification process (what you said).
Your product is excellent..the quality of work, the end result..it is largely responsible for making my bike the pleasure to ride that it is. My Banshee, too.
I am sorry for any misunderstanding.
Merry Christmas, indeed!
Posted: 05:31 pm Dec 21 2009
by RBD
10-4 Canyon and Merry Christmas to you and yours,
It would be very interesting to see how the JD needle would work with the proper fine tuning on one of my modified carbs, I think it should work well.
I have done quite a few carb mods for other brands of 250's and 300's that are running the JD needle and the customers seem to like the combination. I usually get the carb after they tried the JD kit first and still wanted a little more....
I would love to get some feed back from someone that has tried and use the JD needles in the modified KDX carb. I am sure the jetting will be a little different than the standard jetting that I use with the CEK and DEK needle and other mods.
Happy Hoildays,
Ron
Posted: 06:45 pm Dec 21 2009
by canyncarvr
Thanks, Ron.
FWIW...I don't expect any sort of wonder miracle thing. If I had to point to one thing my bike doesn't do well when it comes to throttle response, power delivery, and general carb-ed-ness...well...there isn't nowhere TO point.
It runs great!
But...I've been in the 'It's never run like THIS!' group lots of times, too. That little green machine never ceases to amaze me.
Hence..I'll give JD's needles a shot.
I'm getting the 'standard' kit for the KDX. It comes with 150, 155, 160 and 165. I'm currently running 38/150/DEK-4.
I
asked about them skipping the jets in the middle..thought that was odd.
The answer was: 'Because we are able to address the jetting more efficiently, it is really not necessary to make such small adjustments.'
I can't say I understand that..but..hey. I don't understand a whole lotta things! And I find more of 'em every day!!

Posted: 07:10 pm Dec 21 2009
by skipro3
One thing about that main jet size; Unless you're getting WOT or close to it, the size isn't as critical one might think. At least, not where it's not adjustable with a needle position and all. I'd think it would be more important to get some of those clip spacer things so you can move a needle in half clip increments. I hardly ever go more than half throttle and even then, it's for very short bursts. A wide open throttle on a KX 250 is a little frightening. On a well tuned KDX, equally so.
Posted: 12:22 am Dec 22 2009
by Mr. Wibbens


canyncarvr wrote: It comes with 150, 155, 160 and 165.
Seems kinda a waste
3 of those jets I'd never use unless I go to the dunes
Posted: 11:42 pm Dec 22 2009
by IdahoCharley
I'll give up a little information for those looking into the JD needles with RBD'd carbs.
Yep we do like the JD needles very much in the KDX 200. Run them for 2 years now in the KDX.
After a few tanks of gas through the replated cylinder this spring we dropped the jetting from a JD blue (3) to JD red (3) with a 42PJ and a 152MJ. (Could go to a JD red 2.5 position on the clip with a 42PJ and a 150MJ in 75 degree + weather at 5000 ft but would need to watch it a little closer. In the earlier part of the day at ~ 55-60 degree temperatures it felt a little zingy. )
Normally we are semi-agressive trail riders riding from 5000 - 9500 feet this summer - Raced one team race this summer (finished 4th out of 12 teams in 5hr race) and we made it to the sand dunes twice this year.
At the St Anthony sand dunes around the last week of Sept or first week of Oct just went back to the JD blue (3) and bumped the MJ to a 158. Mark rode hard at the dunes and the bike performed flawlessly. A quick run through the gears 1-4 felt VG to me after the bikes warmed up when we first arrived. Tailpipe was smudge/dry after running the dunes and almost a tank of gas.
I really think this is one of those mods that rate equivalent to say changing the reeds from stock to a V-Force reed block: Very noticable and worthwhile once you dial the jetting. The other thing I like about the JD needle is that it is very forgiving relative to temperature changes and elevation changes. The area where the taper changes occur just seem to be more correct for the throttle positions that I'm usually relying on - if that makes sense.
No it does not make the bike stand on the rear wheel in fourth gear but the bikes response is meaty in the rpm range where I want it. I do not like to scream my bikes but I don't lug them either unless the situation requires it. I previously had run the CEK/DEK and 1370LS series needles with good success with a #7 slide in this bike - but I will not be going back to those needles. Yep the JD needles are a few bucks but money well spent IMHO.
Bottom line 42PJ 152MJ JD red(3) works very well for us at 5000 + feet from 50-90 degrees although 80 + degrees and higher elevations will feel better with MJ 150.
P.S. KDX 200 with RBD'd AS carb, V-Force 3, PC2, and RBD'd head, 13:50 gearing
