The JD needles, Blue and Red, are several diameters apart, not even close. When they work for a certain altitude and temp they work good, but for a seasonal temp change one clip position is sometimes too much and going from the red to blue or visa versa is way too much change on the dia. The NECx and NEDx are 1/2 clip position apart and available in a complete range of diameters. So are the OEM series needles, and the factory chart reflects these finer changes.
Right now we have this JD needle issue with my friends GasGas. Blue is perfect in cool spring, fat in summer. Red too lean period.