DO NOT run your 270 with the throttle stop backed out in stock form. It will over-rev and over-heat and you will have major issues.
Kymco did the restrictions so that the ATV would be legal for a 14 year old to ride. The restriction is in the CVT.
If you are an adult, 16 or older, you can change the CVT Variator Shaft to the one used in a MXU300. The part number is:
22105-LBA7-900 from any Kymco dealer. They are about $27.00.
If you don't know what you are doing mechanically, I would have the dealer install the part. Then you can run it with the throttle stop backed out all the way and go way fast.
Don't mess with the CDI, there is nothing to mess with.
Change the shaft and you will be happy.
CJS