2005 EC250 Jetting

theexception_03

New member
After many hours and $$ spent I have finally got to this set up, still not 100% but its so much better than its ever been

N3EW #3 (I have tried DDK #3 which has a similar effect)
170
38
A/S 2.25

Very sharp and responsive off the bottom end, pulls hard thru the mid range.

WOT is good from low to mid rpm but once it gets up into the high revs it starts to miss again like its running rich. I am assuming that at WOT both the pilot and main are working together. I am a bit nervous to go any leaner on the main.

I really like the N3EW and DDK, is it worth trying a needle that is longer eg DEK.
 
wow... im no expert but yep, sounds lean. in my 250 i was playing with the N3EW with a 42/178 and i thought that was too lean. gone with a N3EG but on a 38/180. was runnin a 178 but it kept gettin hot if i ran it hard..
hope you got your bike runnin good now though... rip it up...
 
After many hours and $$ spent I have finally got to this set up, still not 100% but its so much better than its ever been

N3EW #3 (I have tried DDK #3 which has a similar effect)
170
38
A/S 2.25

Very sharp and responsive off the bottom end, pulls hard thru the mid range.

WOT is good from low to mid rpm but once it gets up into the high revs it starts to miss again like its running rich. I am assuming that at WOT both the pilot and main are working together. I am a bit nervous to go any leaner on the main.

I really like the N3EW and DDK, is it worth trying a needle that is longer eg DEK.

At WOT you are ONLY on the main.
Do I read that you are opening the throttle wide open off idle and as it revs it is clean at low to mid RPM and then blubbers as the RPM catches up to your throttle position?

I can't imagine achieving proper jetting with that technique. There must be throttle control such that the throttle position somewhat matches your RPM. Its true that at WOT and low RPM the signal is weak (less airflow) so the main provides less fuel and keeps things somewhere close. But the pilot and needle are there for a reason.
 
My 03 250 likes to be a little leaner off the bottom than most, I run...
185 main
JD red needle 3rd clip
42 pilot
#7 slide
About 2 turns out on the air screw

IMO the gasgas bikes dont seam to be consistant jetting wise from one bike to the next, I'd like to know the squish on some of the bikes that need to be alot leaner than others I bet its huge.
 
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Another fellow NW EC250 owner here, '03.

I too worked on jetting quite s bit searching for Nirvana.

I tried it all and ended up with :

CCK #2
170
38
#8 slide

Temps 45-90
Elevation 500-3500

I don't think you are too lean. My plug is perfect tan and I have many hours on this jetting with great results.

Mine runs spot on! Absolutely no bog, hesitation or hit. Just smooth crisp delivery throughout. It feels like my EC300 in terms of power delivery.
 
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Without temperature and altitude specs, not much help can be given.

I jet my 05 DE250 (RB Designs carb and head mods) for 110F in Phoenix at 2,000 feet using 168/40. 168 (or 162)/38 in Flagstaff at 8000 feet an 85F. Using whatever needle RB-Designs gave me. :)
 
Without temperature and altitude specs, not much help can be given.

I jet my 05 DE250 (RB Designs carb and head mods) for 110F in Phoenix at 2,000 feet using 168/40. 168 (or 162)/38 in Flagstaff at 8000 feet an 85F. Using whatever needle RB-Designs gave me. :)

I forgot to mention the temps and altitude

Where I ride is sea level and the temps at the moment are between 10'C-16'C
(50-60'F)
 
At WOT you are ONLY on the main.
Do I read that you are opening the throttle wide open off idle and as it revs it is clean at low to mid RPM and then blubbers as the RPM catches up to your throttle position?

I can't imagine achieving proper jetting with that technique. There must be throttle control such that the throttle position somewhat matches your RPM. Its true that at WOT and low RPM the signal is weak (less airflow) so the main provides less fuel and keeps things somewhere close. But the pilot and needle are there for a reason.

I probably explained it wrong, here is a better example...

If I am riding in 3rd or 4th gear at 1/4 throttle then open it up to 1/2 and then WOT (smooth throttle control) the bike runs well until the revs get high and it starts to 'miss'. Its definatley not lean, so I could be hitting the rev limiter?

I am glad to know that at WOT its only the main jet working, that means I could try 168 MJ. Its so surprising that I am at sea level and have to lean it out so much. All of the settings that were recommended for my bike are all too rich. Even the bike shop couldn't jet it properly.
 
Just keep an eye on the plug and for any signs of running lean. Pinging, high/hanging idle, boiling or excess temps.

The bike isn't using any tranny oil is it?? Certain its not a main seal weeping? As the revs increase so does the vacuum which can effectively pull more oil through a leaky seal. Maybe measure the oil from the trans and make sure you can get out what you put in.
 
What I find surprising is that you compare the DDK so closely in performance to the N3EW. DDK is a LOT richer in straight diameter. The N3 needles are a little fat at the tip like the Keihin C and D series and the JD needles, so the needle will have a little control of fuel at full throttle.

My bike picked up overrev with a 185 main, using the JD Blue in clip #4. Things are just about perfect, but its a hot and humid summer here now. A full clip position is usually too drastic a change, plus if you have to run a needle in either end position there is usually a better choice. My concern is I have limited options for cooler weather. I may start to experiment with the NED* and NEC* I have, of pick up some N3 series. The straight dia of the JD Blue/45 pilot/#7 notched slide is a perfect balance in the bike. Starts in half a kick, responds to 1/4 turn of the air screw, and has nice response. This is why I wrote off the NED* and NEC* needles initially because of the leaner straight sections.
 
What I find surprising is that you compare the DDK so closely in performance to the N3EW. DDK is a LOT richer in straight diameter. The N3 needles are a little fat at the tip like the Keihin C and D series and the JD needles, so the needle will have a little control of fuel at full throttle.

My bike picked up overrev with a 185 main, using the JD Blue in clip #4. Things are just about perfect, but its a hot and humid summer here now. A full clip position is usually too drastic a change, plus if you have to run a needle in either end position there is usually a better choice. My concern is I have limited options for cooler weather. I may start to experiment with the NED* and NEC* I have, of pick up some N3 series. The straight dia of the JD Blue/45 pilot/#7 notched slide is a perfect balance in the bike. Starts in half a kick, responds to 1/4 turn of the air screw, and has nice response. This is why I wrote off the NED* and NEC* needles initially because of the leaner straight sections.

NEDF might tickle your fancy Glen.

I have to come out past 3 turns on the AS to get my bike to idle with a 45 pilot, J diameter needle, and #7 unnotched slide. I've since gone to the W diamater which gives some more burble but better response.

Using the tacho on the trailtech I get better rpm using a 178 than a 180. I think I can still afford to drop a few sizes. RPM maxed out around 9300 with the 178. Only 9000rpm with the 180.
 
The JD Blue is supposed to be a modified N3E*, with a richer midrange taper. I don't think I can afford to be any leaner in the midrange. The NED* and NEC* get progressively richer here so perhaps thats the place to start. I'm running a very light flywheel setup so whats smooth on a heavy 2K-3 setup might rev quicker and seem more snappy on my bike.
 
well I am down to this setting;

N3EW #2
168 mj
38 pj
A/S 2.5

Best performance since I have owned it, finally after 33 different set ups I am nearly there.

I will be testing this set up off road at the end of next week....can't wait !!!
 
The JD Blue is supposed to be a modified N3E*, with a richer midrange taper. I don't think I can afford to be any leaner in the midrange. The NED* and NEC* get progressively richer here so perhaps thats the place to start. I'm running a very light flywheel setup so whats smooth on a heavy 2K-3 setup might rev quicker and seem more snappy on my bike.

The NECx/NEDx needles aren't really smooth as in unresponsive. Its just that the bike pulls at whatever position you hold the throttle. There are no abrupt transitions from rich to lean like you can get with other needles. Its very much if you want to go faster just open the throttle further. Feels about as 4T as you could make a 2T.

Heres a little something for you.. You can see the straight diameter is about the same. The first taper ends a bit earlier on the NEC, and then has a richer diameter through the middle. It then continues to flow more fuel into the top end.
 

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Jake,

Thats a pretty good comparison. Reading into what JD has said, and this is before the NED* needles appeared in the Suzukis, the JD needles may be somewhat between the N3E* and NED*, NEC*. Problem is no fine tuning options, Blue to red is way to big a jump. I think I may order some NEC*, NED* with richer straight sections, as I know I need that. Richest I have are H diameters now.

Any luck finding a 2K-2 down there? The kid with the KTM I want to compare has not been around all summer. I will find out ASAP if it is possible.
 
well I am down to this setting;

N3EW #2
168 mj
38 pj
A/S 2.5

Best performance since I have owned it, finally after 33 different set ups I am nearly there.

I will be testing this set up off road at the end of next week....can't wait !!!

Glad to hear that you have it close. From there it should be easy to fine tune to your exact power delivery needs.
Its good that you've been wrestling with a 250 or there may be lots more work yet to do (like a squish mod...) It seems that out of the box the 250's are easier to tackle than the 300's.

Good Luck!
 
I just ordered:

NECF
NEDF
NECG
NEDG

Now I will have quite a range of these. We will see how this goes, as far as I know no one has tried the richer straight diameters, as most of you guys have newer bikes/newer carbs. This thing sure likes richer specs to make power, but it does make good power. I'm going to pull the top end, set the deck, and have the head done in a couple weeks. Check the reed block, throat as well for anything strange.
 
Look forward to hearing how you go Glenn.

I ran the NECW#3 in my 250 last week and it was rich/slow off the bottom. Not weak or flat, just lazy. Also had a small rich stumble as it would go to the middle taper, and would load up a touch in single track. They supply good fuel right through the top end. I think a NEDW#2 would have done it well for me but went back to N3EW#2 instead and found explosive power delivery.

In regards to the richer needle diameters I think you'll find the F/G almost perfect. From my previous readings when first hitting the forums, Pobit suggested N3EG#3 for an aggressive setup, and alot of others moved to G diameters with the stock N1Ex range of needles too.

I emailed trailtech last week to see if they offer a lighter flywheel to fit the GG 2k3. Might be easier to bring a bit more snap into it that way without reducing lighting power. I'm nowhere near smart enough to work out the actual effect different weights or ignitions has on the engine though.
 
Short answer is that your 2K-3 has almost twice the inertia of a 2K-2 with a 14 oz weight. No way for you to lighten that flywheel, trail tech does balance flywheels though. I really like the light setup, if the bike is jetted decent it will not stall, and responds instantly.
 
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