I also know that our members have experienced some issues with Zongshen engines. Some of these issues have happened at very low miles. We do NOT have statistics on fail rates, but one key sentence in my post was that Zongshen probably has more than 10x the number of units (engines) in service. 10x more than Lifan, that is.
They sell LOTS of engines!!!
Also, Zongshen allows rebranding, so Zongshen engines have other logos on them !! It is possible, in fact, that some engine internals in the Lifan engines come from Zongshen manufacturing plants.
The clue to detecting this is that the engine ID stamp shows ZS172-xxx, or ZS167-xxc, for instance as model number. Many of Zongshen's clients don't bother to rebrand. Zongshen just supplies the engines. Zongshen is literally the "Honda" (clones) of China.
It would be instructive to have real data on fail rates on engines that are NOT mistreated. We could do an anecdotal pole but it would hardly be representative
