Electronic Tach on a Mutt Bike

[0medo]

Hey all! I recently picked up a 2000 GS500E in great shape save for a beat-up, somewhat rusty tank and a nonfunctional tachometer. These would have put me off, but the bike was running so well and was so fun and natural to ride compared to some of my previous experiences I couldn't say no. I saw the threaded bit at the bottom and thought 'hey, it's just missing a cable, we'll find one cheap and hook it right back up!'

As it turns out, it wasn't that easy. I got the cable for just shy of $15, went to connect it... and discovered where the tach should go into the head nothing but a vestigial stud. I had been looking for information on the bike and now realized I had an oil cooler - not at all a feature of this year (or any, to my knowledge) of the GS500E model. I gathered the engine must be that of a 2004+ GS500F, and that I would need an electronic tachometer to match. Dialed up good ol' fleaBay and found a decent-looking one with wires and such intact (after waiting a few days to see if anyone would bite my wanted thread here) and now I'm eagerly awaiting its arrival. I haven't even dug into the bike to see what sort of state the electrical system is in, or even what year it's from - to my knowledge, a few bits are incompatible between the two, so I'm unsure if I've been left with a newer or older harness.

Either way, I'd like to find as much information as possible on how this tachometer is supposed to connect to a regular 04+ system, and how to splice it into an older one if need be. I've got very little experience tackling electrical stuff and not much more in general wrenching, but I do have a decent set of tools and more confidence in my ability with them than I should have. General advice would be greatly appreciated, and I'll try to post updates here once I tear into the poor thing.

[gregjet]

I ditched my heavy tach/speedo and I am replacing them with an electronic speedo/tach made by Acewell. They also appear under other names in other countries.
This is the one I am using ( this is an Aussie site . Plenty other countries):
http://www.s3performance.com.au/buy/acewell-3701-digital-speedometer-tachometer-with-pilot-lights/ACE-3701

I used this one because it has the same idiot lights and the stock one. I have used these before quite a bit on my race bikes and they are pretty reliable. one thing though. DON"T play with the buttons once set up or you will be out with the instructions to get it back  to the set up you want and the instructions are correct but ...er...a bit cryptic. You can also get you speedo exactly accurate using the wheel rollout set.

[0medo]

Alright, after a weekend's worth of fiddling, cursing, and forgetting to take pictures, my bike is now fully functional! I re-used the lightbulb from the old tachometer and split its +12v and ground for the new wiring, and ran the signal to the RH coil. Works like a charm! Some might be bothered by the now completely mismatched gauges or the hot-pink zipties holding my electrical-tape sheathing to the frame, but function was prioritized over form. The tank got some new teeny scratches as well when I was bumbling around getting it off, but it was already in really rough shape as it was, so I'm not too concerned.