Tach check?

[trasbeck]

Is there a test to see if the tach is receiving whatever it needs to register? I wonder if the tach itself has died or if there is something else amiss. It worked OK while I was trying to get the bike running, then quit on the first real ride. I tried to disconect the rev limiter wire from the TCI but didn't think I damaged anything. How would I check the signal and wiring?

Also, on Syracuse NY Craigslist Sept.29, is a 1983 xz550 that is listed for parts.........(not by me..)

[QBS]

I'm a little rusty here, the tach gets its' signal from the spark coil hidden in the steering head area.  There is a wire (grey or grey stripe, maybe) that attaches to the spark coil and goes to the back of the instrument unit.  Check for clean connections at the spark coil.