It sounds to me that you might be too lean at part throttle. You might have a vacuum leak, which would cause the fuel mixture to be lean. What do the spark plugs look like. How fast are you going when your in 5th gear at a steady throttle? I'm not trying to insult your intelligence but I'm wondering if your are lugging the engine too much.I know on my 01 FXD I can't get into 5th gear before 50 mph.H.D. motors make tremendous amounts of low speed torque but they don't like to be lugged.carycr said:Fifth Gear, thx for the reply.. Yes that is a Mustang wide touring seat, very comfortable.. Along with the SE slip-ons, I installed the SE air cleaner kit, changed the slow jet from a 45 to a 48 and removed idle mixture adj. screw plug and fattened idle mix by 1 turn.. The vibes seem to come in after bike ridden for say, 30 miles and continue until bike started the next day.. Engine pings most of the time at steady throttle 4th or 5th gear.. It's troblesome..