Needle size NECJ vs N3EW


13 replies to this topic
  • arnego2

Posted 20 May 2011 - 05:50 AM

#1

Hi all
What is the difference between needles NECJ and N3EW? I run with the NECJ but at 75% throttle it starts sputtering. I went from main 178 to 180, 185 and last 190 but I think it is the wrong way. I see black smoke when going full throttle. So I'll try a 175 and would go with the 4rth NP to make it richer. At the moment I use NP3 but with the 178 the plug looked too bright to me, grey - whitish to be exact.

The N3EW looks broader, will that enrich the complete range of the needle compared to the NECJ? So I could stay with the combination of 175/48/NP3 airscrew 1.75 turns out?

Regards
Arnego2

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  • adam728

Posted 20 May 2011 - 07:15 AM

#2

Sputtering = rich
Bog = lean

N3EW vs N3CJ

J is a larger diameter than the W, meaning its slightly leaner in the straight portion of the needle (very small throttle openings)

The E is 1/2 clip position different than the C. So at the 3rd clip on a N3EW the needle sits the same height as the N3CJ would at a 3.5 clip position.

N3E starts its taper sooner than the N3C, so it begins to richen up sooner.

So in all respects the N3EW is richer than the N3CJ.

I'd do a wide open plug chop and read the dark ring at the base of the insulator to really determine what main you need. I'd personally start with a 178 jet. Then start tuning part throttle with needles.

Edited by adam728, 20 May 2011 - 09:20 AM.
flipped letters...


  • arnego2

Posted 20 May 2011 - 08:37 AM

#3

Hi adam
Thanks for that it helps a lot, great info, :smirk: I hace planned a ride today and will put the N3EW into the carb at NP3. I thought first that sputtering is too lean. But I saw yesterday the smoke at WOT.

regards
Arnego2

  • yamahasocal450

Posted 20 May 2011 - 09:02 AM

#4

Sputtering = rich
Bog = lean

N3EW vs N3CJ

W is a larger diameter than the J, meaning its slightly leaner in the straight portion of the needle (very small throttle openings)

The E is 1/2 clip position different than the C. So at the 3rd clip on a N3EW the needle sits the same height as the N3CJ would at a 3.5 clip position.

N3E starts its taper sooner than the N3C, so it begins to richen up sooner.

I'd do a wide open plug chop and read the dark ring at the base of the insulator to really determine what main you need. I'd personally start with a 178 jet. Then start tuning part throttle with needles.

The J is larger diameter than the W... W -> Richer and the J-> Leaner. You're right about the e vs c

  • adam728

Posted 20 May 2011 - 09:21 AM

#5

The J is larger diameter than the W... W -> Richer and the J-> Leaner. You're right about the e vs c


Whoops, you are right. I looked at it right, then wrote it wrong. Edited my post to correct the info and not confuse anyone. Thanks.

  • arnego2

Posted 20 May 2011 - 09:41 AM

#6

hmm now I'm sure that the NECJ is smaller in diameter than the N3EW. Although just comparing it by eye.

As you both compared the N3EW vs N3CJ, the former will still make it richer than the NECJ, if I got that right. And that is what I'm after: a throughout tat richer but leaning it against WOT. As at 75% throttle the main is the principal player. Sputtering happened from 178 to 190 all the way.

  • spinner38

Posted 20 May 2011 - 02:13 PM

#7

i would try the 175 main, it sounds really rich. not much needle working at 75%

  • arnego2

Posted 20 May 2011 - 04:07 PM

#8

Hi guys,
thanks for your help! The riding was wicked :smirk: no more sputtering, runing very nice, from down end do the high end even the throttle 100% worked out and the plug looks a tat better then before; still grey but almost brown. I used the 175/48/NP3 1.75 airscrew turn. I did not do a plug chop as here it is hard to get the spark plugs. I have a new plug which I could used Bosch, Super plug WR7 8X.

Best regards
Arnego2

  • hallsy

Posted 20 May 2011 - 04:50 PM

#9

Hi guys,
thanks for your help! The riding was wicked :smirk: no more sputtering, runing very nice, from down end do the high end even the throttle 100% worked out and the plug looks a tat better then before; still grey but almost brown. I used the 175/48/NP3 1.75 airscrew turn. I did not do a plug chop as here it is hard to get the spark plugs. I have a new plug which I could used Bosch, Super plug WR7 8X.

Best regards
Arnego2


There has been 3 different needles mentioned in this thread N3EW, N3CJ and NECJ. Which one did you use with this jetting?

  • arnego2

Posted 20 May 2011 - 05:30 PM

#10

At first I used NECJ with 178/48/NP2 the grey plug was too bright, than went to 180/48/NP3 and 185/48/NP3/ and 190/48/NP3 all did sputtering (also the 178) and now I went to the N3EW needle which 175/48/NP3 and it did not sputter at all.

I run the fatty with the PC304 silencer and Vforce reeds @ 100 to 2000 feets

  • hallsy

Posted 20 May 2011 - 05:46 PM

#11

At first I used NECJ with 178/48/NP2 the grey plug was too bright, than went to 180/48/NP3 and 185/48/NP3/ and 190/48/NP3 all did sputtering (also the 178) and now I went to the N3EW needle which 175/48/NP3 and it did not sputter at all.

I run the fatty with the PC304 silencer and Vforce reeds @ 100 to 2000 feets



Ok thanks, so getting back to your original question of NECJ vs. N3EW. Do you realize that NECJ is a Suzuki needle, and not the same as the Yamaha needle N3CJ?

  • arnego2

Posted 20 May 2011 - 05:52 PM

#12

I'm aware of that. I used it because I was not able to get the neddle out of the carb I had for that engine. So unable to compare numbers I just assumed that they are identical. I bought a ratched kit and did finally get that needle out seeing that they are different.

The NECJ is slimmer seen by eye and was most likely the cause of the sputtering. Lesson learned. On that bike I mix Suzuki parts which Yamaha parts. After all it is a RM250 frame with a YZ250 engine. Now the engine is as snappy as my YZ250 :smirk:

  • hallsy

Posted 20 May 2011 - 07:37 PM

#13

I'm aware of that. I used it because I was not able to get the neddle out of the carb I had for that engine. So unable to compare numbers I just assumed that they are identical. I bought a ratched kit and did finally get that needle out seeing that they are different.

The NECJ is slimmer seen by eye and was most likely the cause of the sputtering. Lesson learned. On that bike I mix Suzuki parts which Yamaha parts. After all it is a RM250 frame with a YZ250 engine. Now the engine is as snappy as my YZ250 :smirk:


Yes it is slimmer at the tip, but at the other end they start with the same diameter.
Posted Image
The blue lines indicate the taper starting points. The NECJ has 3 tapers compared with 2 tapers on the N3CJ. From the straight section down to where the 2nd taper of NECJ starts the two needles a very similar. Once the 2nd taper starts on NECJ it begins getting smaller than N3CJ. The third taper further reduces the NECJ diameter. The smaller the diameter the more fuel that is allowed to pass by, making the mixture richer. Typically you would look at going 1 or 2 main sizes leaner with NECJ vs. the main used with N3CJ. Some prefer the Suzuki needle to the YZ needle, consider trying NECJ with the same settings as those you prefer for N3EW but use a leaner main jet. In other words if you like N3EW-3, 175 main and 45 pilot. Then try NECJ-3, 172 or 170 main, and 45 pilot.

  • arnego2

Posted 21 May 2011 - 02:43 AM

#14

Thanks, good info, I'll file that away though as at the moment I prefer to ride the bike. I took out that carb 5 times over the week and it was rather frustrating not to get it right.





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