Here's the deal. the reason some benefit and some don't is becase as i said before, TBS needles are longer than many needles. therefore, if the taper isn't much richer than the one in your bike, the length may actually make them overall the same or even leaner. Example: the needles in my speedy were tapered a bit thicker, BUT, they were considerably shorter. So with the longer TBS, at any given point in the jet the thickness was probably the same or even thicker. Look at the pic below and it should be clearer. Use the red line as an example of a given point of the needle within the jet. Even tho the needle on the right (TBS) is thinner tapered as you can see by the tip, because it is longer, at the point within the jet where the red line is the TBS is thicker. Shim it and it wont be.So it depands on the length compared to YOUR current needles
