Jetting questions and considerations
 

Question to you all but especially @Jakobi (who has excellent knowledge about jetting).

After ten years of jetting KTM's and now more or less new to GasGas and the needles which are used I have some questions. Of course I could use KTM needles but I lost all my data about them and I try to solve a problem with a buddies bike. But let me tell you some facts first.

My buddy does not want to buy a JD kit which I use in my 300 successfully.

The problems with his 300 were the same that I had: excessive fuel consumption, blubbery and overly rich down low! No figures, no discussion necessary.

On both bikes I adjusted the way too high float level and did the James Dean loop. That didn't change much. It was good with the JD_red needle on mine and even better with the NECW needle on his. We both ride a lot in first and second gear doing slow tricky stuff with small throttle openings.

The original N1EF (clip 3) needle everyone seems to hate worked good and I still like it but its way too rich down low from closed to 1/4 throttle and it gives bad response. Dropping the needle one clip helped here but made it too lean in the mid range. I admit I did not test a smaller pilot jet and left the 42 installed.
My bike is fine with the JD_needle and a bigger main jet but as he didnt like to spend money I purchased a NECW needle as it has been recommended after some discussions on TT.
I installed it in 3rd position, tweaked the air screw and let him ride for about 3 hours and another 3 hours a day later.

Fuel consumption was significantly lower, even better than on my bike, response was super crisp. But there was a slight, just noticeable hesitation in the transition when the throttle was opened over 1/4. Kinda flat spot that is caused by a lean condition. He did not like that and I wasn't sure which needle to try next as I had given my complete Keihin needle kit to the new owner of my previous KTM. In TT a NECH was recommended but I did not buy one as it is the same as the NECW just with a richer starting diameter. So that in my opinion makes no sense.

I am not familiar with the NECx and NEDx needles nor am I familiar with N3Ex needles.
Thanks to Jakobi I learned the NEDx is a triple taper, which I'd prefer over single or dual taper needles. Allegedly it is crisp down low but has a richer mid range.

What puzzles me, I have been told that NECx and NEDx are the same except that NEDx is a clip (or a half) richer.

Can anyone point me in the right direction please?


PS: If I had not lost my hand written jetting book that contained 10 years of experience with KTM needles the bike would already be perfectly jetted. but I lost all the info about the differences of the KTM needles, so start more or less from zero :(

PPS: learned that the JD_jetting_sheet can't calculate NECx and NEDx needles.

Spot on mate.

What clip position is the NECW in? Have you tried going a clip position richer? 1/4 - 1/2 throttle is most impacted by clip position, so I would do that.

If a full clip on the NECW is too much, then as you've said.. NEDW is the half clip richer version (same taper profile).

In my 2013 I always ran 40 NEDW#2 175. In my 2018 I'm at 42 NECW#3 175. I could probably go richer on pilot/diameter as AS is just past 1 turn from seated.

These Suzuki needles have a long straight section compared to the stock N1EF as well. So in some ways the diameter will impact small throttle opens. But by 1/4 throttle you're usually well onto the needle. The delivery is rather smooth..

And if you want an OEM needle that is 'similar' to a JD Red, I'd be suggesting a N3CH/N3EH (C being half a clip leaner than E). Couple it up with a bigger main like you would with JD too.

The set up was NECW in 3rd position, MJ: 172, PJ: 42, can't remember the airscrew setting.

Great, what you say is what I had planned, to lift the needle one clip. Unfortunately I could not further play with the carb as we are under a strict lock down. But I hope that we will be able to continue in 4 to 6 weeks. At least I hope that. From what I have felt when riding his bike I expect that one clip down (#4) will give the right amount of additional fuel to eliminate the slight hesitation. It is a very slight hesitation I first did not notice but he did. And after concentrating I could feel it too. So I will first try with NECW in 4 and if it is too rich then, which I don't think I can try the NEDW in 3.

Ok, I will order a N3CH, a N3EH and a NEDW. I hope FrankMX in the Netherlands will have them in stock, but I am not in a hurry anyway.
Personally I like the JD needles and I was surprised about going up with the main jet but when I saw the needle it was clear. Its visible to the bare eye that the JD needle(s) are way thicker at the tip than the standard N1EF.

The tapers of the JD needles are almost not visible and I like how smooth they are. Some racers here do not like them but I do not race and don't ride much WOT in high gears. From time to time on faster bits but I can not remember that I ever held the throttle full open in 5th or 6th gear for longer that 10 seconds. I am just to old for higher speeds.

Jakobi, you helped me a lot. Many thanks! I really appreciate that you took the time to to point me in the right direction.

No worries Doc,

You'll see the same difference between the N3 and NE needles too. The Suzuki tapers off a whole lot more towards the pointy end.