I have a honda that is "cold blooded" like your bike. Some bikes naturally need to be choked to start. Make sure you check the spark plug, and see if it is the manufactures´ recommended one. Turn the gas off when you are not going to ride for a while,,, like over a weekend, or 3 or more days. Have you done any modifications to the exhaust or air filter from stock configurations? If you have, you may want to get a tune up for slight modifications,,,, or Re-jet the carb if you had major mods done!