This is great news. It took some research to come up with a solution. Thankfully, it was a cheap solution. I had all the bits to build it in my stash of connectors and components. If I get chance I will post the schematics for the device and get it made a sticky. As these bikes get older the electronics will start playing up. If you see a cheap ECU or dash on eBay then buy it and squirrel it away for a rainy day. Glad to have helped out. Pay it forward.
I think myself extremely fortunate and will certainly do my best to aid anyone where I can. It's been quite the crash course, and without the support of this forum (and special mention to ChrisW), I am confident that my Tacho would have never worked again!
@El Toro is there a way to extract this and make it a sticky in the technical section. The circuit was developed to address an issue on an IAW16 ECU but it may work on other ECUs that use a square wave on the Tachometer signal. The idea is that the square wave signal is boosted to 12v. Components needed 1 x N27000 Mosfet 2 x 1 KOhm resistor Copper backed circuit board to solder components onto 4 x lengths of wire The only wire from the ecu that needs cutting is from Pin 24 on the ECU to the tacho
I think it's very kind of you to supply details Chris - I can think of several other professions where they would sit on this in secrecy and cash in at the appropriate time.
I agree, this should be a permanent guide on the technical section. However I did read recently that P8 ECU tacho's are not compatible with IAW 16's???
Found this on https://www.actronics.co.uk/ecu/magneti-marelli-iaw-16m/iaw16mar look what they list as a common problem
Evening all I thought I would just finish up by showing the final result on the bike (see pics) Apologies to ChrisW in advance. He is going to notice that neither of his have made it onto the bike. This is purely because I'm a ham fisted moron and broke them both. So.....I bought the bits and made a third one exactly as he has described. To fix to the bike, I disconnected the ECU plug and stripped back the loom covering. I then cut the green/grey and the brown wires The gizmo was then soldered in, and then everything was bound up onto the loom so it's tidy (ish). The earth is the ECU fixing. Tacho is 100% working and we are away. Thank you once again to everyone on the forum, and absolute Kudos to ChrisW and his electronics knowledge! If anyone comes across this post and needs one, and can't get hold of ChrisW, let me know as I have enough stuff to make about a million of them.