Re: China Motors....
I agree with Dave on upgrading the head also, I dont un the stock heads anymore since my bike are run in this really hot dry Texas climate and I ride mine fairly harz and fastfor many miles at a time usually, I dont ride mine to my work alot but when I do its a 32 mile round trip and I run wide open a good part of that since about 22 miles of it is wide open road.
The Puch heads do a great job, dax sells them already drilled for the 8mm studs or you can get the Puch hi hi 70cc head from treatland.tv also but youll have to drill the hole out yourself since they're set up for 6mm studs.
The 6cc chamber Fred head is an excellent head, looks great and does a good job of keeping the engine cooler running.
Like Dave has said for just putting around its not as big of an issue in my opinion either but for long hard runs the heads with more surface area to wick heat away from the engine add life to the engine by helping it to run cooler.
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!