You need to go all out and get this one.
http://cgi.ebay.com/ebaymotors/160CC...em190203181426
Don't know if it really makes a difference, but this one actually says "lifan" on the sides of the engine.
Here might be a great buy.
http://cgi.ebay.com/ebaymotors/110-L...em120228956614
There are so many parts available for these engines that are of good quality that it shouldn't be of much concern for you.
Go look in the pit bike section as that will have alot more info on these.
Allen