Will a 21mm PWK Work On a Stock 49cc 139QMB GY6 50 Maddog?

Last 21mm PWK on a 50cc Maddog was super successful.  It gained 4mph.  Viewers pointed out that it was not a good 50 test as the bike had Naraku 52.4mm Big Bore Kit (90cc) and NCY Cam.  Viewers were correct again.  In this video I test the Chinese Keihin knockoff on a true 49cc Icebear Mad dog.    

Tuning and Installing PWK 21mm  Maddog 50 Gets 21mm PWK Flat slide Ca...