Yet another NT jetting problem.

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Derek75

New Member
Apr 19, 2018
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Just got this thing broken in. I went through and did some mild porting, and cut the notch in the skirt on the intake side of the piston. I also shaved the head a little with sandpaper on glass. X-Port with stock exhaust, billet intake with o-rings, cone air filter. Oh, and and an NT velocity stack.

Out of the four notches on the needle, the second from the bottom makes it run and go fantastic, but the sucker won't idle. Moved the clip up one (richer) and it idles beautifully, but sputters at WOT/max RPM.

I did go one stage richer from stock on the main jet. All it did was reverse the symptoms. Either I can rev like a champ, and hold my thumb on the throttle to keep it running, or go one notch down and it'll idle all day.

Crazy thing is that the plug chops are all Hershey's favorite color, no white ash, no fouling.

I am running a thumb throttle, but the slider moves as it should.

Vacuum leaks have been checked with carb cleaner.

**PS** overall, since getting it broken in and polished, this is the only issue I have.

Also.... I have been trolling y'all for months, finally threw my hat in. :D
 
Last edited:

crassius

Well-Known Member
Sep 30, 2012
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moving clip up makes it leaner - moving needle up makes it richer - not sure which you are doing here
 

Derek75

New Member
Apr 19, 2018
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That's precisely my point. Clip goes north, runs great at 1/3 to full throttle, won't idle. Clip one notch south, idles nice, bogs at full throttle. No in between.
 

crassius

Well-Known Member
Sep 30, 2012
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no idle with screw all the way in means rich - drop needle to get idle back, then work out from there

clip does nothing for tuning - it is just how you move the needle up or down
 

Derek75

New Member
Apr 19, 2018
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Clip does nothing for tuning? I thought it regulated fuel flow at WOT? Higher=less fuel....lower=more fuel. How is that nothing for tuning?
 

crassius

Well-Known Member
Sep 30, 2012
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the needle does the tuning - the clip just holds the needle in place

once you have the idle, you check plug to see if you are rich or lean at WOT