sounds like this is a simple fouled plug, replace the plug and don't leave the bike idling for a long period of time, get out and ride it till good and warm and kill it for test one, if it doesn't start then one more time replace the plug while it is still warm and try agian if the plug you took out looks fine (not black and oily) then I might suspect the plug wire possibly where it enters the coil. if it doesn't start after replacing the plug, check the coil connectors, coil mounts for rust/corrosion, also take a look at the wires comming off of your kill switch. I feel this is a simple problem from the description you have given START SIMPLE AND WORK YOUR WAY UP