I have a DRZ supermoto that has been sitiing in a garage for about six months with a full tank of gas. I started it the other dat, it ran for about 5 min then stopeed and would not crank over again...Any ideas??? What happened???

Did you check your air filter before starting it? How did it look?

I would drain the old gas out of the tank, clean out the fuel lines and clean your carb. The old gas most likely gelled up and clogged up the carb. Once all that is done run premium gas or the highest octane level in your area and try startin it again. Another test to see if that is it before you start taking everything apart is the spray some starting fluid in your airbox without the filter on while cranking the engine over. If it starts you know the engine is not getting gas. If it still wont start you may have something else wrong. Good luck!

Along with what was already posted, it's probably a good idea to check the valve clearance, and inspect the cam chain and tensioner as well as the spark-plug. And as an after thought, do you plug your exhaust for storage? It might be a good idea to check and make sure nothing crawled in!

Are you saying it won't crank over, as in "locked up" or "seized up"?
If that's the case you may want to pull your spark plug and attempt to turn it over by hand.
Could be a broken piston ring, or scored cylinder wall.