I ride a 99 ktm 250exc and im trying to clean up the jetting some as i know these bikes are rich off idle. ive already ordered a single taper needle, and i also want a #7 slide as ive heard those help alot too and right now i have a #6, i just dont want to pay the price of a # 7. Some people have recommended that I can just file mine to a #7..? is this something that is possible, and how would I go about filing it, is there a way to measure it (for example, 6mm to 7mm, or is that not how its determined?) any tips are much appreciated. thanks.