The stock N1EF has a very short straight section, which is also overly rich. It then tapers off quickly. You usually end up with nice off idle and a lean hole in the middle, or a fluffy bottom that snaps to life as it clears out.
Both the Suzuki and Yamaha/Ktm needle has a longer straight section which really helps to dial in the idle and off idle. The Suzuki is probably a bit leaner feeling off idle, and has much less taper through its profile. Steady supply of fuel. The Yamaha/Ktm is a dual taper and you really do feel the transition between the two. It almost leaves a small lean area in the middle/upper rpm where the engine transfers onto the pipe. You end up with a smooth grunty bottom end, and a wild top end on the pipe, with a strong transition between the two.
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