running out of fuel?

[cchracer77]

created a monster

So I followed the fuel curve idea. Started thinking that maybe was a bit fat through the middle (hence the loaded plug, due to clip position) and lean on the top. I figured that this would cause the cases to load up with fuel, then once they cleaned out it would go lean. When I was looking at the needle profiles I posted I found it hard to believe that the N3xx and the NExx were so far apart, but both have a following. Thought that maybe they were both off to either side of what the bike would really like. I took my measurements, a really lean taper old brass needle that I had lying around, chucked it in the lathe, and made the needle labeled "MOD" in the attached chart. I have to say that after a short test rip around town, I'm sold! Installed it on 2nd clip, with 40 pilot and still 165 main (only change 1 thing at a time). The main now shows a touch lean, but other than that it's the crispest thing I have ever ridden! It will pull all gears and wind for minutes in 6th. Also, kudos to the law officer who turned a blind eye to my test.

 

[Todd5774]

So when you selling some needles then?!

 

[Neil E.]

What units are used for the X axis and Y axis?

 

[cchracer77]

All of my measurement tools are in S.A.E. So x is length , y is diameter, both in inches. X is measured out from the bottom clip.

 

[Jakobi]

Who can we get to start producing these?? I'd be sold..

I find the same. The NExx is either a bit lean off the bottom and fat in the mid, or the N3xx is fat on the bottom and goes a touch lean in the mid..

 

[cchracer77]

After some more seat time and fiddleing, I settled in on 40 pilot, as 2.25 out, the needle described above on the 2nd clip down from top, and a 168 main. The combo seems to work from 5k-9k ft, over a broad temp range. After playing with my spreadsheet data some more, I have found that the needle is basically a 2 clip leaner copy of N1EG. This indicates that I'm running 1 clip leaner than the top clip on a N1EG, at lower elevations you may get the same results trying a N1CG (if it exists) at the leanest setting.

 

[Jakobi]

A NOZG at top clip will be half a clip leaner than the N1EG at top clip.

I have a NOZJ to pick up tomorrow. Not sure if I can be bothered installing it though..

 

[cchracer77]

A NOZG at top clip will be half a clip leaner than the N1EG at top clip.

I have a NOZJ to pick up tomorrow. Not sure if I can be bothered installing it though..

Seems worth a shot, whenever you get to it. I noticed, in my "tests," that the bike liked the richer base diameter needle. Leaner through the middle, and fattening back up on top. My observation was that it let me run a leaner pilot jet, with closer to the keihin recommended 1.5 turn a.s. setting. Helped to prevent erratic idle issues.

 

[Jakobi]

I hear you.

I found the opposite. That with a fat diameter and a lean pilot that I could get a nice idle, but 1/8th throttle would burble up more than I liked. Coming out on the AS to clean up 1/8th would leave the idle mix too lean.

I got around this by going to a leaner diameter and a bigger pilot which allows me to run the AS at 1.5.

Realistically the diameter doesn't make a whole lot of difference unless if you are chasing perfection.

I could run any of the above and be happy enough. 35 G, 38 H, 40 W, 42 J, 45 K.

 

[Jakobi]

Adding to this, it also depends a bit on the particular needle you are using as to the effect it will have. On the N1E/NOZ series the straight section of the needle is very short meaning it only affects a small section of the throttle position. Moving to a Yamaha needle with a longer straight section you will notice the changes in diameter to be more profound.

 

[cchracer77]

Adding to this, it also depends a bit on the particular needle you are using as to the effect it will have. On the N1E/NOZ series the straight section of the needle is very short meaning it only affects a small section of the throttle position. Moving to a Yamaha needle with a longer straight section you will notice the changes in diameter to be more profound.

This where I noticed the differences, the needle I turned out, being 2 clips leaner than the N1Ex series, hangs on the straight diameter longer, like the N3xx needles, then richens up faster in the last 1/3. It cleans up the 1/8th throttle blurble, while not being unduly lean in the last 1/3.