If your n/t won't idle.

[Greg58]

While tuning a nt on a friends bike that would barely idle with the idle screw turned all the way in I found the problem, it turns out that either the needle is too large or the top of the jet is small. That being the part of the jet that the needle slides down into when at idle, I noticed that the e-clip was in the top or leanest slot so I lowered it two slots reassembled the carb and the engine now idles with the screw backed out like it should be. On the nt that I have this was not a problem but it seems that on some this may happen.

 

[2door]

Greg,
Did you happen to check to see if the jet was screwed all the way into the bore? There have been many cases of the jet being loose or completely out of its bore in the NT. It should have a screwdrive slot where you can insert a screwdriver and make sure it is bottomed out.
Tom

 

[Greg58]

Yes, I did check. I found it odd that these carbs are not all the same. It looks like the needle taper is not right near the tip.

 

[Greg58]

Tom I was thinking of measuring both needles when I get a chance just to see what is differant.

 

[2door]

Greg,
I've not experienced any significant differences in needle length in any of the NT carburetors I've worked with. That's not to say you won't see it.

There has been some discussion in the past about modifications to the needle taper but I've never found a need for it or experimented with that pareticular mod.
In case you're not aware; The needle only controls fuel flow up to about the 1/2 to 3/4 throttle range. Anything over that is strictly a product of jet size as the needle is raised out of the orifice of the jet and therefore does not have an effect on flow.
Tom

 

[Greg58]

At anything over idle this bike ran good, looks like the needle was almost sealing off the fuel flow.