dropping front cylinder

i have a 96" S&S with stampede ign/torque cones /vance and hines exhaust /super e /carb turbulator / bike runs very strong /recently have had 3 separate times when while crusing it drops front cylinder / plugs clean/new wires/good 240psi compression / once ran perfect all day stopped for 1 hour when started dropped front cylinder , waited 20 minutes and it started fine and drove home with no problem ,good sunoco fuel /all connections good / wtf?  

after much contemplation and more than a few Budweisers , i re gapped the plugs to .28 and retarded the timing by a hair , and she is screaming again , this one threw me for a bit because it would come and go and I finally realized it had to be a simple fix , I was getting ready to pull the head ,thinking bad valve/spring , cleaned the carb more than once , and really wanted to pull my hair out ,oops to late ! anyway easy fix once i added alcohol !