I'm using EC Calc program to calculate dimensions for a pipe on my 50cc Sachs Columbia. I'd like to be able to use a belly stinger (the video comparing the sound reduction sold me on that!) but I'm not quite sure how to implement it. From what I understand, it's basically just a bleed orifice, so the only two things that should matter are length and diameter, correct? Or should I design the stinger to extend inside the chamber? Another thing I don't quite understand-- why is a belly stinger necessarily longer (as per EC Calc usage page 2)? I was thinking of making a short one and putting it towards the top of the chamber to protect it. Can I just use the 7mm diameter (on the high side my given stinger diameters) by 4.5 inch long value? And does the end of the chamber necessarily have to be the diameter of the stinger if the stinger isn't end-mounted? I took a look at the rest of Jaguar's site today-- definitely going on my bookmarks tab as I try to get as much out of this old bike as I can! Thanks for your time, and all your hard work and research, sir!