OK I did the Nyroc muffler mod (6 3/8 holes but did not remove all of the spark arrestor only the internal portion and left the hole in the end cap the stock size) and added the Napa hose with stock air filter.

Changed mains to 142f & 145r, stock needles shimmed .035 and screws are at 2 1/2 turns out.

It starts and idles better than ever and there is no hesitation anywhere also the plugs are a dark tan to light brown but...

The problem is it coughs slightly at 1/8 to 1/4 throttle, once above 1/4 it smoothes right out and takes off.

Would this be a pilot jet too lean, more shimming of the needles or a finer adjustment of the screws?

Thanks guys jetting can be so frustrating at times[img]i/expressions/face-icon-small-blush.gif[/img]

 

Adjust the mixture screws somemore. Maybe this article will help.carb
One way to help troubleshoot whether its lean or rich, remove the air box cover, and if it improves...youre rich, if it gets worse youre lean.
Or use the choke... if it runs better, youre lean.