2010 Jetting Saga Continues

[Bailey28]

The popular CCK needle with a 38 pilot and a 175 main jet as compared to Jakobi's N3CH. I kept the pilot at 38 for both. Don't worry about the rest of the entries as they are not complete and not showing. The reference line again is the N1EF clip 1, 38 pilot 175 main. My bike spooged a lot with the CCK, although it made more torque.

If keeping the triple taper needle works well above idle, maybe just getting a thicker needle as in Jakobi's case, F to an H, works well to keep the idle area clean.

 

[Bailey28]

Here is the profile comparison for the N1EF-1 and the N3CH 1. Notice the N3CH is a double taper needle, it does not have the extra rich taper from 3/4 to full throttle. N1EF is in black and the N3CH is in red.

 

[Bailey28]

This graph is interesting. I took the N3CH, made the diameter an F for comparison sake, and overlayed it onto an ACL needle profile.

If you compare an "A" 1*00" aftermarket taper to the first taper in the N3 series, they match perfectly. An ACL-3 is equal to an N3CF-3 until just above 3/8 throttle. After that the N3CF taper changes to a "C" 1*34" taper at that point. No surprise that the aftermarket needles follow a single taper of any of the double and triple taper needles.

In fact the first taper of our beloved N1EF needles is even more shallow than the "A" taper. This gives only a slight richening over the first part of the throttle. It is almost a straight portion.

Now if I could only find that little Orphan Annie decoder pin.... yes I drank my Ovaltine!

 

[mrkartoom]

What slide are you guys (with the same size carbs) running? If the slide is rich you can screw with needles forever and never get it really good. It will also mess with your pilot ckt as you have to jack the idle screw in. Try a leaner slide and by all means get the squish dialed in when you can. 300s are more touchy than 250s and these details are even more important.

Also, you should jet with the map switch in the hi or sun mode (more advance).

38mm I'm in Sun mode and using the 7.0 stock slide. Are some running 8's or 9's? I've seen others running richer, but that have been on 36mm. Something is messing with my a/s for sure.

 

[Bailey28]

I installed the o-ring and washer from a four stroke fuel screw onto my air screw to get it to stop leaking premix all over the float bowl. I think the o-ring and washer made the screw adjustment hold better, as it is more consistent.

 

[Jakobi]

38mm I'm in Sun mode and using the 7.0 stock slide. Are some running 8's or 9's? I've seen others running richer, but that have been on 36mm. Something is messing with my a/s for sure.

+1 38mm PWK ASII - Always sunny. 7.0 stock slide.

I have run with the pilot as large as 42. All that happens is that I get the tell tales signs of a rich bike. Loads of smoke, spooge, loading up of the plug, excess fuel consumption, and as soon as the bike is warm it won't idle until the idle is screwed in far enough to bypass the pilot circuit.

In saying this the N3EJ is considerably leaner on the overlap of the pilot. I will try a 38 at first and may move onto a 40. As stated earlier/in another thread, a friend of mine is using a 35 pilot with great results. Just have to confirm what needle he is using.

Bailey. Could you please post a graph showing comparison between these needles.

Base - 38 N3EG #1 175
38 N3CH #2 175
38 N3CH #1 175
38 N3EJ #2 175
38 N3EJ #1 175

that would be ace!

 

[Bailey28]

HERE: all of your needles are very close to one another. the
j diameters are leaner on the straight but other than that, not much difference.

 

[Bailey28]

I think the N1EF would be a fine needle if the L1 were longer, as in something less than or longer than the 1st clip, like an N1EF on clip -2

The initial taper of the N1Ex series is so mild and shallow that it appears that it would not affect the off idle richness as much. I think that is why Jakobi and others have gone to a larger diameter to help cure the richness at idle.

I think the bike would idle well running on only the pilot circuit and with minimal intrusion from needle pullover.

I would like to try a N1EH or N1EJ with a 38, 40, and 42 pilot.

 

[Bailey28]

Ok, just fooling around with the program, here are the comparisons so far:

Base Needle: N1EF clip 1 all needles compared to this one!

N85F clip 3 is the same as N1EF 1 everywhere

N4AF way richer from 1/8 on, then leaner at 3/4 on (2 taper)

N3CF leaner 1/8 to 3/8 then leaner from 3/4 on (2 taper)

N4DF leaner at 1/8th, richer at 1/4, then leaner at 3/4 on (2 taper)

N3EF leaner at 1/8, same at 1/4, leaner everywhere else

NAFF richer from 1/4 on but same profile as N1

NALF way rich at 1/4, same profile as N1

N6MF richer at 1/8 only (2 taper)

N8RF same needle as N3CF on clip 2

NFTF leaner at 1/8 then very rich at 1/4, follows same profile as N1 but rich

N3VF rich at 1/8, then leaner at 3/4 on (2 taper)

N3WF leaner from 1/8 to 1/4, then exactly the same as N1EF1

N2ZF 1/2 clip leaner than N1EF1

NOZF same as N1EF1, 1/2 clip leaner as well.

There you have it... The N1EF taper has the longest straight section of any of these here with the exception of the N3CF and EF tapers... however the N3 tapers take longer to get to the richer midrange taper than the N1 does, which could cause a flat spot in the midrange.

 

[Jakobi]

Heres the sound of 38 N3CH#1 175 after my test ride yesterday. Obviously its on the stand so doesn't count for much. Will try and get some audio/video of riding either this afternoon or over the next few days

http://www.youtube.com/watch?v=UZkzUAOKy_0

 

[GMP]

It should not be this hard. I'd try a #8. My 250 runs perfect with a JD Blue and a #7, and a 300 is a bigger pump with a bigger signature. It fixed a couple 300s here in the past, one in NY state so approx 0 - 1000'.

While the slide cutaway is described as affecting the same range as the needle straight dia., from experience it is a bit more broad, overlapping the low and mid more.

FWIW, If you send the carb to Ron for his mod, one thing he does is cut your slide leaner.

 

[Bailey28]

I'm happy with the way mine runs. I think we are looking for the perfect jetting, everyday, no matter the altitude, temperature, or load on the bike.

As I look further into the 2 stroke jetting I am starting to believe that our engines require vastly different fuel curves depending on what situation they are in.

Just putting around the yard or up and down the road? I think they need less fuel.

Climbing a steep hill while lugging it? I think that calls for more fuel.

Cool temperatures outside? More fuel

Heavy sand? More fuel

Hot temps on hard packed trails? Less fuel.

I think a 4 stroke is a little more forgiving with less/more fuel here or there. Our 2 strokes complain, bog, ping, and spooge if their butts aren't powdered every so often with a clip change here, air screw turn there...

And let's not forget the wide range of fuels throughout the world, and the range of oil mixtures, oil types, spark plugs, air filter cleanliness, gearing, altitude, hard or soft dirt, reed condition, engine wear and rider preference.

 

[Jakobi]

It should not be this hard. I'd try a #8. My 250 runs perfect with a JD Blue and a #7, and a 300 is a bigger pump with a bigger signature. It fixed a couple 300s here in the past, one in NY state so approx 0 - 1000'.

While the slide cutaway is described as affecting the same range as the needle straight dia., from experience it is a bit more broad, overlapping the low and mid more.

FWIW, If you send the carb to Ron for his mod, one thing he does is cut your slide leaner.

Its not that hard GMP. I have been happy with pretty much all the needles I am playing with. All have worked well in the bike. I worry sometimes that I am going too lean compared to what others are using.

Other than this I am just looking for the best setup for me. Power where I need it without being too much of a handful Fine tuning and learning along the way. As I heard once before, it only takes a few minutes to make a change, and if you never bother to give it a try you'll never know if its any better.

 

[Jakobi]

Tried the N3EJ today on #2. Wasn't overly impressed with it anywhere.

Rode again with N3CH #1. I like this alot but I think its a bit on the lean side. Especially coming into winter.

Settled with N3CH #2. The bike idles well. Pulls smooth and strong in the bottom end. Punches into the mid and rips in the top end. The smooth bottom end could be a bit crisper but I also feel it lets me ride smoother which results in less fatigue.

I will do the unthinkable and change my fuel ratio to 40:1 to add some extra lubrication now that I'm starting to show the bike more throttle, and hopefully this will also lean things out just enough to keep me smiling.

 

[GMP]

When I hear bikes won't idle, air screw does nothing, and the balance is hard to dial in(needle) I think slide. Some are just good and easy, like my 250, others are more demanding like my '03 GG 250 and KTM300 was.

 

[Jakobi]

When I hear bikes won't idle, air screw does nothing, and the balance is hard to dial in(needle) I think slide. Some are just good and easy, like my 250, others are more demanding like my '03 GG 250 and KTM300 was.

Thanks for the help.

I found I had issues with this when the needle I was using was far far too rich. Once I tapered back down I can get the pilot working with the slide and it transitions well. I'm just stuck between clip positions to get me the best throttle response from 1/4 - 1/2.. Some are too lean, others too rich. I had dreams about this even! Its consuming me! haha.. Time to stop jetting and go for a ride again.

 

[Bailey28]

I thought I was the only one who dreamed of jetting!

 

[mrkartoom]

I dream about riding. I have nightmares about jetting.

 

[Jakobi]

The dreams will stop when I stop stressing and start riding! Its the wondering what catches me.. When I'm riding I couldn't be happier with the bikes performance (well not much, but hardly crosses my mind)

 

[MJC]

I've tried almost every Needle and jetting combo on this site, and the best combo i've come up with so far for long smooth responsive power From 0'-2000' here in upstate NY for my 11' 250 is.

Needle= NEDW 4th, optional needle from an 07' Suzuki rm 250.
Pilot=42
main=175
AS=2 turns out
Stock slide