I have an 06 Road King Police and the other day the speedo climbed to above 120 and is now not working. any ideas?

Check gearbox end for snapped cable

My 2001 road king just did the same thing. The speedo would bounce up and down then quit altogether. Turns out the battery cables were loose. This caused the voltage to the speedo to be hit and miss. I tightened mine and it works great. The odometer had power but registered no miles. Pull the seat and check the cables. Got this fix from a local friend who owns a bike repair shop.

No this will not work. unfortunately Harley has changed their seats and frames a couple of times since 2002 i would search for a 2009 2010 or 2011 police edition seat.

Usually the air temp is cooler in the morning and more humid. I don't know virtually anything about the electronic fuel system in the bikes these days but I'd suspect one of the sensors connected to the fuel system. Your bike does not know what time of day it is. It may have a temp sensor on it though.

Hey did you find out what it was, cause I have a 2005 RK and it did the same today. Checked all the fuses all are intact don't have a clue as to what the cause is.

Try holding your key fob button down for about 20 seconds. This may resync the alarm. If that doesn't work, it's most likely in the speedo. You can try cleaning the speed sensor for the speedo. It is magnetic and picks up metal shavings which short it out. Pull it out of the trans and wipe off the shavings.

If your unit is cable driven, get yourself an old piece of cable and insert it up into the speedo and then spin the cable while watching. If the needle jumps its pretty much assured the speedo head is ok and that your problem is in the cable or in the front wheel. Bill