Scooter-Station notes that Haynes has released one of their famous service manuals targeted to Chinese/Taiwanese/Korean scooters. Probably handy, but it can’t be too specific, even though half the scooters made in Asia are Yamaha Vino knockoffs, there’s a lot of variety there, too, and surely a wide variety of tolerances and torques and such, which is where the Haynes manuals usually shine. Still, knowledge is power, and even if it just covers GY6-style engines in depth, it’d be useful.