Electric tachometer repair

Has anyone had any experience rebuilding an electronic tach? I have a 95 kz1000P with a tach that stops working after a few minutes. I've checked all the connections, and they all seem clean and without corrosion. I have repaired mechanical speedometers and tachometers before, but i've never cracked open an electric one. Is it worth the trouble to get open or should I just get a new one.

I would start by checking the "crimp" connection in the loom where the tach takes it's signal from (one of the coil trigger wires) as these do corrode over time) you can check the signal pulse with an LED

The crimp looked good but I will definitely go over them with some some steel wool upon re-assembly. I got into the case as well and i was hoping to find something obvious, like dirt build up or a loose solder joint. But it all looked really good.   

Curious if there's a way you can let it run without the cover on, long enough that it would normally stop working. I had mine ('84 KZ700) apart recently. The electrolytic caps on the board were toast. They're the small "cans" on the circuit board. There's other electronics in there that will be intolerant of heat as they age. Can you try to get some pictures of the circuit board? Top and bottom if possible.
Another possibility is that one or more solder joints is cracked and "opens up" when things get warm.
When you say "stops working", does that mean the needle drops to zero? does it fade to zero? does it get stuck at a certain point?

I've replaced capacitors in tvs and a couple of other home appliances. very easy. here's a kzr topic for a KZ700. 
www.kzrider.com/forum/6-paint-a-bodywork...ew-gauge-faces-maybe .   "Also replaced the 3 electrolytic capacitors on the tachometer PCB. Very easy to do, and now they'll last another 40 years. Very easy to do. And likely needed replaced anyways. Electrolytic capacitors have a finite lifespan.  The values were: 6.3V 470uf, 16v 47uf, and 50v 2.2uf. I'm *assuming* that they were the stock capacitors."