LT racing jet kit report...
 

Hey all,
Just got my jet kit in from gofasters and I can say "BULLY!". Things have cleaned up nicely from1/8 to wide open. I still have some sputter from
closed to 1/8 so I reduced the pilot to 45 from 48 (airscrew at 3 turns out).
It's better, but I want perfection so in will go a 42 asap. Then I should be able to run the A/S at about 1 1/2 out. all the sputter is gone from the previously sputtered up throttle positions. Yah Whoooo!!! I also swithched to the sunny setting and WOW does this 300 go. I love my gasgas mucho better now!:D

Jim,

I usually drop the needle one spot (clip up one) to remove that sputter. What position is the clip in?

Hey Eff,
the clip is in the middle position as requested by instructions. I didn't think dropping the needle would clean up the off idle richness that's one reason it isn't already done. thanks for the tip. I'll try that first.
I heard from my local gasgas dealer not to run below a 45 pilot, but if I can't get the airscrew below 2 1/2 turns out I've lost the adjustability of the airscrew to lean out that circuit. I will report back how that adjustment goes.
thanks!

Try an #8 slide if it won't clean up with a smaller pilot.

The instructions are based on 60ºF I believe. Refer the the std jetting chart in the manual to change from there.

I was running the 48 pilot, air screw 3 turns and the clip in the middle. I took my bike for a spin after I put on the LTR 126MM links (a couple of weeks ago). It sputtered, and was clearly running rich. I popped open the carb and raised the clip one and turned the air screw to 2.5 turns and things ran smooth.:)

took it out after dropping the needle 1 position. temp around 80. with the a/s 3 turns out it was very close, but I'd still liketo drop the p/j to a 42 and run the a/s about 1 1/2 out which give me latiude for adj either way. I must say over all this jetting set up is very good. thanks Les Tinius!
jetting when I'm finished should be as follows:

mj=178
pj=42
jneedle=2nd position from top
a/s= ~1 1/2
#7 slide
:) :p :D

This carb is fine up to 3 turns out on the air screw. Les told me that this carb is designed to have the airscrew in that range. I believe he was told this by sudco (keihin importer for u.s.).

jeff

With the 42 pilot and airscrew at 2 1/2 turns temps at 84 deg. the carburetion is more clean, but just after cracking the throttle open it doesn't sputter it's more like a raspy hesitation (It may be just part of the characteristics of the engine). I put boyesen dual petal power reeds on my 200 and that same situation cleared up. Maybe since I have the v force3 reeds it is causing the same lack of super smooth acceleration at barely open throttle position (I don't know)
I do know that everywhere else is awesome. smooth powerful acceleration!!

The reeds shouldn't do that, mine runs smooth and clean off idle. Try the #8 slide, borrow one if you can. Start back up to 45-48 on the pilot and middle needle position. The 250s seem much eaiser to dial in with a #7 than a #6. The 300 being a bigger pump may be eaiser with the #8. If the slide is rich the rest is a PIA.

Much thanks I'll give that a try!

I went ahead and ordered a #8 slide because it can't hurt to have it around anyway. Report to follow after it is installed.

Look forward to hearing how you get on with the number 8 slide, I've been having very similar issues with the LT kit. It's damn near perfect but I'd like to know if the 8 slide cures those little niggles.

LMAO!! Yea those "little niggles" need to go away!;)
It makes sense the #8 slide would work because it's just at the crack of the throttle that the, in my words, "raspy hesitation" crops up. I've never had to change a slide before to get perfect carburetion, but there's always a first.

That hesitation with the 42 pilot LTR needle#2 178 main is caused by being too lean on the needle straight section diameter. Going to a #8 slide will only make it worse. Go back to the #3 clip with the 42 pilot and 175 main and it will work better. Even in the #3 clip the LTR needle is border line lean at off idle at sea level 70 degrees so don't run the air screw out too far. Other options are CCK#3 for a very smooth power band or a N3EG#3 with a 175 main for a stronger mid to top pull. These are sea level settings at 70 degrees F. oil mixed at 40:1 pump gas 91 octane. If you want really clean and crisp jetting, you need to have the cylinder head cut to reduce the squish and get a cleaner burn. Otherwise the jetting will always be a little dirty in hot weather no matter how you jet it. Dave

cck#3 is a type of needle??

:D jimbolaya, try what POBIT says before anything else, he is pretty damn good at this stuff, and the advice he gave you is very good... ( Just my 2 cents )

I will certainly check it out. thanks!

Yes, try it, should tell you if your roughness is rich or lean. There all different. My '07 runs awesome on what would foul my '03. And yes, have RBD cut the head. RBD also does carb mods that have excellent reviews. I beleive he cuts the slide to an #8 and works from there as part of the package.

The latest LTR needles should be richer in the straight section than previous that were indeed lean.

[QUOTE=GMP
The latest LTR needles should be richer in the straight section than previous that were indeed lean.[/QUOTE]

The LTR needles I have are sold as -0 needles and measure 2.66mm in diameter. This needle in my 06 300 was lean in the #3 clip 42 pilot and caused the bike too hit too hard at off idle causing excessive wheel spin. The other two needles I mentioned have a softer off idle hit that works better for picking your way through rocks or roots. The CCK is mellow throughout the entire power band and the N3EG gives the bike a more motcross like feel with a healthy mid range hit and a nice over rev if you use a 175 main. Keep in mind I have the DE ignition on my bike so it is more responsive to leaner jetting. The LTR needle may work fine at off idle with the heavier EC ignition as the heavier flywheel will have a dampening effect on throttle response. I do think the heavier ignition would benifit from the N3EG needle to help the slower reving motor spin up faster. Dave

Something doesn't add up. Dave, your LTR needle measured 2.66mm on the straight dia.? That would make it richer than the CCK (K=2.695mm). If you were lean off idle with the LTR needle I would think that the CCK would make things worse all else being equal.

300s are tougher to get perfect plus I think you tend to ride them at lower throttle openings, making those adjustments more critical.

What effect does your ignition map switch have on this? Did you jet for one position or the other?

The LTR needle and the CCK have the same straight section diameter. The LTR needle has a longer straight section diameter length so when you run the LTR needle in the #3 clip it is leaner at off idle than the CCK in the #3 clip. That is the point of the CCK needle. At idle, it is the same diameter as the LTR needle so you get a clean idle. As you open the throttle, the CCK enters the taper sooner making it richer giving the motor a more torqy feel that is easier to control. At about 1/2 throttle the CCK starts to become leaner than the LTR needle and this helps the 300 rev out better. The N3EG does the same thing but is a multi taper so it gives the motor a MX hit in the mid range.

As for the two Maps, The leaner the jetting is, the bigger the differance is in the two maps. With rich jetting it is hard to feel any differance between the two. With lean jetting, there is a big differance. I jet for maximum power in the MX mode and then use the rain mode to mellow out the power for the tight stuff. Dave

I understand all this, you just confused me at first with that 2.66 mm number. The CCK and LTR -0 are the same dia. but should be 2.695 mm, unless something has changed recently. The -1 had a leaner taper, and the original LTR needle from '01 had an even leaner dia of 2.705 like a CCL. Les doesn't make these from scratch, they start life as a standard Keihin needle. This is also true of the JD needles.

Hey pobit I sent you a pm ... did you get it?? umm or did I hit the wrong button when I sent it off???

Anyway who makes and where can I get one of these cck needles???

Standard Keihin needle you can get from Sudco or Carb Parts Warehouse.

thanks
I'll have to give one a try.

Just to clear things up, James at JD Jetting designs his own needles and they are a triple taper needle design. The needles made by Keihin for the PWK carbs are a single taper needle.

Also, I do have the CCK needle in stock.

Ron

I received a few emails asking me to clarify how these needles differ in feel so below is a fuller description. These settings are for sea level, 70 degrees, tested in a 06 DE300 and a 06 DE250. The bikes are American DE models with the lighter ignitions, stock GG pipes and FMF Turbine Core II mufflers. The motors are stock with stock base gasket height and RBD head mods. The stock #7 slide was used for all needles. Pump gas 91 octane, oil mixed at 40:1

45 pilot LTR-0#3 175 main:
Slightly lean at 1/8 to 1/4 throttle giving the bike a hit at off idle and then the richer end taper makes the bike feel weak from mid to top in the 300. The motor will idle cleaner with a 42 pilot but this makes the 1/8 to 1/4 throttle hit even harder. Works better in the 250 than the 300 as the 250 is still able to spin up with the richer end taper and the hit at off idle isn't as strong. If LTR would radius the transition from the straight section to the taper to soften the hit, it would be a good needle for the 250.

42 pilot, CCK#3 178 main:
Very smooth, easy to control, torqy power from bottom to top with no hit anywhere. Works in both 250 and 300. Good choice for those that prefer throttle control for picking your way through rock gardens or tough survival rides. This needle also works well for novice racers who get tired before the end of a race and struggle with throttle control.

42 pilot N3EG#3 175 main:
This needle is for racers and gives the 300 the most power with a strong mid to top pull. My 300 has the dual ignition and this needle in the MX mode makes for a lot of mid to top power. For slower, tight riding, I ride with the ignition in the rain mode and this takes the edge off the power and makes it more controlable. In cold weather you will need to use the 1/2 clip richer N3CG#4 with a 178 main or you will get a little rattle from mid to top. These needles do not work in the 250 as these needles are too lean on the end taper and make the 250 too revvy. I race A class and this was my favorite for my type of riding.

45 pilot JD red#3 175 main:
This needle in the 300 feels like the N3EG needle on the bottom but does not pull as strong from mid to top in the 300. You get a clean bottom pull with a more torqy, mellow mid to top pull. A little too mellow for my taste. In the 250, it gives the bike a torqy mid to top and doesn't hurt acceleration. This would be my first choice in the 250 although at $80.00 for the kit, it is way over priced. For about $7.00 you can make your own crude JD red copy from a DDN needle. This needle has the same straight section diameter and a 45 degree taper simular to the JD's end taper. Chuck it up in a Dremel and sand the transition from the straight diameter to the taper at 34 degrees. This will make it a multi taper with the first taper at 34 degrees and the second taper at 45 degrees. The JD red is slightly lean in cooler weather at off idle so If your going to make your own, A DDL may be a better choice with it's smaller straight diameter. DDK has the same diameter as the JD blue.

Hope this helps, Dave

Ron,

I think JD himself said the JD Blue for the PWK38 kit is based on a DDK with additional taper cuts. This is a good needle.

Glenn, yes the DDK needle and the JD Jetting blue tip needle have the same straight section diameter and both of them have a very similar L1 length, but this is where the similularities end. Both needles have very different taper profiles (DDK = single taper, JD = triple taper). If you were to measure the JD needle as a over all straight taper (average from start to the end of it) it would be....., well only close to the "D" taper needle.

Comparing the DDK needle taper to the JD taper, the DDK needle taper starts out richer (JD needle starts out leaner than the DDK). At the L1 point they are the same. There is a point in the middle of the taper that is close to being the same. At the wide open end of the needle taper the DDK needle is richer than the JD needle (JD needle is leaner than the DDK).

Another thing to take note of, is that the taper on the JD needle starts sooner than the DDK needle. Even though both needles have a similar L1 length, the LI length is NOT the starting point of the taper. The L1 length is a point measured on the taper where it is measured to be 2.515 mm in diameter to the top of the clip #1 groove.

I hope I said this in a way that can be understood by most of you out there.

Ron

In my 04 DE300 I had the LTR -0 needle and it worked ok but had a hit in the midrange that was a bit too much in the woods at times. :eek:
I took Pobit's advice and went with a CCK needle clip position #3, MJ178, PJ 42 and it worked GREAT! :D
Very smoooooth power in the woods!
Thanks a lot Dave!

I've finally gotten my #8 slide installed on the 300 and I'm happy to say it has done exactly what it was supposed to do. The low end throttle response is completely clean and with my airscrew adjusted for the temp of the moment it runs as good as it can. Having the head redone might make things work even better, but for now performance of the engine is fully acceptable.
Color me one happy camper:D

Glad it worked out for you.

Thanks for the CCK suggestion. It is smooth.

I had gotten the head squish tightened up and although the milled head noticeibly improved the low end power , it also accentuated the flaws in the stock jetting. (#38, N1ED #2, 180) The hit right off idle with the stock jetting was then a handful in tight woods. The CCK will be a big help with smoothness.:) :) :)


2001 300 XC

Now try the RB Designs carb mod. You will be amazed. The low end tunability range is huge. Top end is sick fast...

Which one the following needles N1EC N1EF N1EE N1EG N1ED is most similar to the N3EG#3 needle. I live in sweden any idea where I could buy a N3EG needle.

//Toni

Toni. You can also try a N3WF or a N3YF , They are powerjet Kawi needles 99-02 I believe. The YF works very well in my 300 but when we tried the same in cactusreid's 300 it would barely run. I'm thinking it may be partly due to his needle jet being worn out of spec.

FYI - keihin doesn't sell a replacement needle jet (aka nozzle) so there wasn't much you could do to compensate for wear in this part. Options were to try leaner needles or just throw in the towel and buy a new carb.

A while back, I mentioned this problem to Ron at RB-Designs and he came up with a solution. He is making up the replacement needle jets that keihin doesn't supply. This old "nozzle" needs to be pressed out of the carb and a new one pressed in. The jet block needs to be removed in order to accomplish this - so you have to send your carb to him to have the work done.

I took a look a quick look at Ron's website, but don't see that he has the "nozzle update" listed - his other gasgas carb mods are listed here...

http://www.rb-designs.com/gasgas250-300.htm

jeff

If I have access to these needles N1EC N1EF N1EE N1EG N1ED how should I jet to get my ec300 run best.
I would be glad if I would get some help in summer and winter jetting.
I live at sea level, in summer time the temp. is round 18 celsius in winter -7.
This summer I have used the following jetting.
Slide #7
42
N1EF#3
175
With these jetting I have a slight hesitation when giving full throttle from low RPM's in the midrange.

As Jeff mentioned above, I do make a replacement needle jet for the Keihin PWK 38 mm carbs.

I machine these nozzles from C360 brass stock. I do this repair for $25.00 plus return shipping and handling.

Ron

All the needles you have listed are the same needle with only a differant straight diameter. None of them will work. The needles you listed have a rich spot at off idle that makes the bike stumble and a rich end taper that makes the bike run flat from mid to top.
The N3EG needle is an optional needle for an 03 Yamaha YZ250 two stroke. The needle for a 99 Honda CR250 part# 1369D it is identical to the CCK except it is 1/2 clip leaner. CCK#3 = 1369D#3.5 These may be easier for you to get than ordering needles from the USA. Dave