As things go the word "slightly" should be changed to excessively. If you look at your Chinese chain you will find that the problem is that when the chain is curved around the crank gear the links spread too much making them too wide to properly fit the gear. Remember the kid thing with the church, the steeple, open the door and see all the people?? Place your fingers together with your finger tips facing you. Open the door all the way and note what happens to your finger tips as you close it. Your finger tips get farther apart. This is what happens to the effective size of the teeth that have to mate with the gear teeth when you wrap the chain around. At that diameter the chain teeth do not correctly match the crank gear teeth. The teeth will wear off very rapidly possibly dumping metal particles down into the oil pan( not a good thing). Seems I remember in the past the set was referred to as a matched set.