I seem to have wired my Tac in backwards and now it is pegged to the far right. Is it shot or is there a way of fixing it? Thanks for any help.

 

Looking in my genuine HD shop manual for 1978 1/2 to 1979 FXS there are three wires to your tach. A blue wire that eventually goes to ground, an orange wire that is for the light in the tach (also a black wire comes from that connection and goes to the speedo light) and a yellow wire that eventually goes to the top primary wire connection on your coil. That same coil connection should have a blue wire from the ignition timer/pick-up and the bottom primary wires to the coil should be two white wires. This is all assuming you have an original equipment type ignition and tachometer.
Hope this helps.
I highly recommend getting a genuine HD shop manual for your motorcycle; it is well worth the dough if you're going to work on your bike yourself.

 

Megawatt

Thanks for the advise. The problem is that I wired it in wrong the first time and started the bike and even with the bike not running the needle is pegged to right. Do you think the tac is toast or is there a way to fix it.

Thanks Again

 

Oh, its stuck there all the time, I see.
All I can think of is to talk to a speedo/tach shop. There has got to be one in your area somewhere.
I'm thinking that its probably just stuck if it went full scale but it could be damaged as well.
I'd take it to a professional since delicate instruments and myself don't play well together.
I hope it isn't too expensive if it needs repair.