CG is a thimble engine developed by Honda and a classic CG 125 model. Most domestic 125 cars use this engine. CB is also a product of Honda, a small chain machine, and a replacement product of CG. GS is the model of Suzuki, and the most representative model is suzuki king. Others, such as Diamond Leopard, En, GSX, etc., are actually products of this series. The engine of GN is the same as that of GS, except that the model is a little prince style, and it is also a product of Suzuki. GT is a relatively new model of Suzuki, which was launched in 2008. It is also a small chain machine, focusing on acceleration performance. YB is a product of Yamaha, including YB Tianji series and YBR Tian Jian series, which is famous for its ultra-low vibration of balanced shaft engine. These cars have their own advantages. Although CG machine is the oldest and generally backward, it is cheap, easy to maintain and has large torque at medium and low speeds. CB machines are used less now, and even Honda will be phased out. Now Honda's engine is gradually switched to the latest OTR/CBF. GS machine has stable performance, low failure rate, durable leather, high-speed performance in design, and GT has acceleration and fuel saving performance. The biggest advantages of YB series are light acceleration, small vibration and low noise.