GY6-200 GY6-B case
GY6-B 16″ wheel BN157QMJ
GY6-B, engine number BN157QMJ and also BN157QMJ-3 , made by BenNeng of Zhongneng Industry group, is similar in appearance to the standard GY6, but is not. Some parts interchange, most do not. They are easily distinguished by the fact that they have a 16″ rear wheel.
Not sure what “-B” gy6 you have? There are many gy6-b engines out there. We make it easy for you to figure out what you have and are also setting some nomenclature standards in our tech section at this link under the article “Trying to figure out the whole B-case thing”