lol, the CB points system works perfect in piston aircraft, I wonder why you cannot get it to work in your mehran.
the reason the CB points pit (which you call carbon) is because the capacitor is not working or the ignition coil is too low of impedance. If your mechanic is an idiot - nothing can help you - they will even burn up the pulse generator and ignitor (what you call CDI).
CB points work ok once you set them up correctly - critical is setting the dwell timing and then correcting the centrifugal advance. Very easy and simple.