Motorcycle Repair: exaust on motorcyle, drag pipes, harley rider

Question
i know it says you only deal with harleys, but this is a general question that could relate to all bikes. I was told that running a motorcycle without an exhaust could cause damage to your valves. I do not know the truth to this but I  have been running my bike with just the header and no exhaust pipe and I don't want to cause any damage. That you for your time. Dan

Answer
Exhaust are designed to remove burned gasses and heat. Running an exhaust to short will cause heat buildup int he heads. Also, unless you rejet, you will run lean. Lean means more heat. So you can furn a exhaust valve.
Lots of Harley rider like to run with drag pipes, which is about you have created. Since you have no back pressure on the exhaust you lose power in the midrange and some in the lowend. What you have done is hurt your performance
Good luck and happy riding
Mike