Jetting (needles) 2013 gasgas ec 250

[nickp]

Does anybody know the main differences between N1EF and NEDF as in leaner or richer. many thanks.

[Jakobi]

The have the same diameter (F = 2.705mm)
They are both triple taper needles, and provide approx the same amount of fuel towards wot.
Based on that, you should be able to use the same pilot and main with both needles, and thats about all. The taper profile between the two are totally different. The N1EF has a really short straight section that leads into a very rich initial taper. This gets people to lean off the clip position to try and clean up the bottom end. As a result the mid range falls flat. The NEDF however has a longer straight and leaner initial taper which means you can get more effect out of the diameter for fine tuning, and run the clip position where it makes the best spread of power across the throttle openings.

[nickp]

Cheers Jake, one more ouestion would you expect bike to run hotter or colder with NEDF as bike seems to run cleaner with this needle, as you said same pj and mj with both needles. thanks.

[Jakobi]

That depends on a few variables, including clip position. Clip for clip the N1EF will be cooler as it'll be burbling and spooging like crazy and using twice as much fuel. Lean will cause excess heat, but with the N1EF and its aggressive taper profiles you'll be more likely to be rich in one area and lean in the other. If the bikes not blowing coolant, pinging, or hanging on idle it'll be running just fine. The stock needle is only good for the bin.

[nickp]

Bike has slight hanging idle on both needles pj42, mj175, both needles clip pos 2. any ideas.

[Jakobi]

Turn the air screw in a bit more
Turn the idle down some more
Try half a clip richer
Ensure no air leaks (check airboot to carb, and carb to reed manifold, remove flywheel and look for signs of weepage from main seal).

What fuel ratio, altitude, and temp. Measured your squish?

[nickp]

50-1 Castrol tts, 631 feet above sea level,average temp over year 20 degrees c is this any help jake.

[Jakobi]

Thanks.

Make one change at a time and evaluate. This way you'll know all is well. Check things as above and then start with a larger pilot jet. Try a 45, with the possibility of going to a 48. This is a AS1 carb isn't it? If you find that all is does is make it fluffy off the bottom, go back to the 42 again and then move the clip a position richer. If it stops the hanging but feels too rich, go and buy the half clip different needle NECF. If its better but still a bit rich off the bottom (1/8 to 1/4) you could try and go a step leaner on the diameter, but this is really chasing perfection, and the F will likely be just right for a 250.