The study of scavenging flow is an important aspect in the porting development of two-cycle engines. The related flow visualization work is usually done with the help of model investigation. The present techniques use water, air, smoke, etc., as media and observations are either visual or photographic. In most cases, the equipment used is expensive and yet the data obtained is seldom complete. The purpose of this paper is to present a promising new method for scavenging evaluation. Use of Diazo paper and ammonia gas is envisaged for obtaining flow patterns. The method is fast, inexpensive, and reveals at least as much data as the present methods. The method as presented in this paper is in the preliminary state of development, but shows promise as a development tool.