The Chinese army arrested Yeltsin soonly after Gorbachev was forced to leave his seat. The popular votes in the SSRs after that made some of the SSRs like the Baltic states to leave USSR, but it's still the largest country in almost all aspects in the world. What would happen if China did't become a part of the USSR, for example Mao's later death perventing the civil war in China that makes it join the USSR? Would the USSR disslove by Yeltsin's coup?
OOC: The Sino-Soviet Union before Gorbachev (at least) includes USSR after WW2, Mongolia, Mainland China, north Korea, Indochina countries (Vietnam, Laos, Cambodia, maybe even Burma) and Afghanistan.
Baltic states, Moldova and the Caucasus countries leave USSR after the popular vote.
OOC and WI: What would the result of the popular vote be in Ukraine? I think the difference is too narrow to predict the result, they may or maynot leave the Soviet Union.