i bought this 28-tooth sprocket to give me an intermediate ratio between the 26 the bike came to me with and the optimistic 30 i bought. i run the bike at the land speed races and needed a spread of ratios to maximize speed. the 1997 buell cyclone would not pull the 30 above 128 mph, but when i switched to the 28 it went 130 at the mile and 132 at the mile point five.
the sprocket is excellent quality, comes with a nut, locking ring, and allen cap screws to hold it in. other kits sometimes include the seal assembly but it's not really needed.