What is the value of a sks rifle serial number 7004197 made in china?

The Norinco SKS rifles haven't attained the value that other makes of SKS (Russian, Romanian, Albanian, etc.) have for a number of reasons. They were manufactured and exported en masse, and, in spite of the ban on further imports of Chinese firearms imposed by the Clinton administration, they're still readily available. For something in good to Excellent condition, with no aftermarket add-ons, you're looking in the $200 - $300 range for the standard Type 56 carbine, though the short paratrooper carbines and detachable magazine models may go into the $400 - $500 range.