I have a 1999 1200C Sportster. It was pretty much in a box when I got it and have put it back together and ride it everyday. Since March I have put 20K miles on it and it has been great. Just recently the tach started to wig out on me. I thought at first it was the primary coil wires but after working with them for awhile seem there is no change. The speedometer also drops out. No matter what speed I am going it just drops out, it comes back but it is real annoying. Anyone have any ideas what would cause this and if the 2 problems are related???

 

Sorry to see you haven't gotten any responses. Not always the easiest site to navigate and some people only look at posts in specific areas. I'd suggest copy/pasting this into the Sportster section:
https://www.hdforums.com/forum/sportster-models-10/

Best of luck...