Nightster won't start
 

Well after being gone for 19 months I finally come home to ride my nightster and I hook it up to the charger low and behold it won't start. Well at first I thought it was it was the battery in key fob had died so I got a replacement battery for that but, then it still wouldn't start I had disconnected my speedometer to sell it and now I'm not sure disconnecting it was a good idea. even with thenew battery in the key fob the little red key light still flashes. Does anyone know if I need to have the system reset and the key rematched to the bike or what?

What does "won't start" mean?
Does the motor not "turn over" (crank), or does it turn over but not fire.
Do you even get a "click" sound when hitting the Start button?
Are your lights burning brightly?

FYI - not leaving the battery on a Battery Tender while gone for 1.5 years, is a guaranteed way to kill it.

Not knowing the exact science behind the alarm system and the key fob, the flashing red light concerns me as though the unit is waiting to be programed.

Often with alarm systems the remotes need to be "installed". The main unit needs to read the code and start communicating with the remotes.

I'd get a service book for my bike and look up the alarm setup instructions.

Also the battery may turn over your bike but may not have enough reserve power to create spark. It may need a boost from a good battery to get it to fire.

I thought if the little red key is flashing, that means the unit is armed. Did you try to disarm it with the fob by pressing the button twice? (like a computer mouse)

The batteries went out in both of my Fobs last month. My bike is an 07 so I thought that was pretty good "milage" on a "watch" battery. The "alarm" was still going off when I had the Fob close to the bike. Once I replaced the batteries it went right back to working fine.