service manual

Hi all, Zongshen promised me 3 months ago they would send a service manual to suit a ZS155 engine. Does anyone have one? Why are they soo hard to get? Surely they make one or are they just decades behind like the Japs were many moons ago? Any help would be much appreciated.

Built up engines for someone who liked to abuse the hell out of em and ended up doing a lot of repair work for him(crashing, ovverevving in 1st, low oil or no oil in gas, list goes on) in the end he had bought a badly beaten up. Ds80 for 800 dollars not running no fenders no airbox bent forks...