My nc30 has the common issue with the flat spot between 4-7k revs. I rejetted carbs earlier this year to 118/120 as I discovered it had 115/117 in for some reason and I have an aftermarket can. When checking the needles I found it had what I believe are none standard needles. They had groves and a circlip around the top so you can change height and look different to the picture in the guide. It also had the standard 0.5 washer. I decided to leave it alone and see what difference the jet change made. Unfortunately it still seems to stutter slightly between 4-7k revs if your not hard on the gas. I read thru the carb jetting thread and there seems to be conflicting opinions on whether to add or remove a washer to solve this as both running rich and lean can cause this problem. Can anyone recommend whether I need to raise or lower the needles. I was going to raise the needle 0.5m but now wondering if the stutter is because it's running rich rather than lean.

My nc30 hated the extra washer under the needles, i think the only way your gonna know is just try it and see wat happens. But i'd try lowering needles by a notch ie move the circlip up the needle one notch.
Cheers
Ian

Adding washers or raising the needle makes the midrange 5-7k'ish richer

Im on factory pro needles with a 1mm drop on stock needles with no washer

Will report back when i get chance to take her out but on my last ride the flat spot was ever so small

Ok, thanks guys. Will raise the circlip to drop the needle. If I remember right it was on the third grove down with one 0.5m washer so probably quite a way out from where it should be.

steve85 wrote:Ok, thanks guys. Will raise the circlip to drop the needle. If I remember right it was on the third grove down with one 0.5m washer so probably quite a way out from where it should be.

heres a pdf of needle sizes etc to compare heights of your clip height based on stock ones

HTH

Rick