Bike won't hold a speed at above 1/4 throttle to 3/4 throttle. It keeps accelerating and then will stall. Would I be better off changing the P6 NJ back to the P8 or is my needle the 9DZH6-50 to lean and I need to get the 9EBY01-50(believe that's the richer one of the two, leaner being the 9EBY01-51.)

 

Sure sounds lean to me, and the needle is the main player at those throttle positions. However, are you sure the diaphagm is seated correctly and not damaged?

 

It helps also to know what you got. Like type of AC, air box modded or stock. But I agree that it could be something wrong besides jetting.

 

clean the carb REALLY good. mine did that to at about 3000 miles. hasnt done it since now at 17,000.

 

Pull carb apart and check for clogged jets. Mine just did that and I had a piece of gunk in my main jet.
Good luck