Motorcycle Repair: Air knocking spark plug wire out, spark plug wire, triumph thunderbird

Question
One of my plugs was loose.  I tightened it and now the Spark plug wire keeps getting blown out by air coming from somewhere.  What is causing it?   The bike runs perfect otherwise, but I know I'm shy one cylinder.  It is a 1998 Triumph Thunderbird (3 cylynder).

Answer
I usually only answer questions on harleys, but I might be able to help. Start the bike and put hand close to the spark plug wire and you should be able to feel the air blowing. Also check the plug wire itself. The clip in it might be bent and not holding tight on the plug.
Good luck and happy riding
Mike