I mentioned the speedo and tacho are both cable drive? The tacho is gear driven via a cable off the end of the horizontal inlet cam. The Magneti Marelli "P7" ECU, developed in conjunction with Ferrari is a lil' like me, not too smart! To get decent tuneability and the ability to drive an electronic tacho you need the up-spec "P8", from the Sport Production models. It's a good ECU though, used for quite a few years on later model 916's right up to WSB level, and has the facility to map each cylinder individually, can run two injectors/cylinder etc. Tuning was both tricky and dead simple. You need to have someone able to adjust ignition and fuel maps and then burn them onto an EPROM chip (tricky) but once you had a chip you just unplug the old and insert the new (easy). It's hard to find someone able to tune maps and burn chips these days but there are still plenty of different chips available for different engine tunes.
Back to the P8 ECU, how to get one for cheap? The "Ducati" P8's go for pretty salty money.......but they are also available in a few other bikes like Laverda's, Guzzi's, and even some cars, so I just picked up an el cheapo Laverda Ghost 650 unit for 1/4 the price of a Ducati unit and swapped out the chip.
This a Ducati P8 ECU from a 916 Strada:
And this is the label on my "exactly the same but different" Laverda unit....the difference being it's a fraction of the price:
Swapping out the eprom is dead easy, just remove the 4 screws from the underside cover (it's Italian remember...) and all is revealed. Take note of the notch in the eprom for orientation, carefully remove the old (using anti-static precautions if you are that way inclined) and install the new:
Job done. Hmmm, too easy, too cheap, so I made a point of squandering extra cash on a completely unnecessary carbon cover like this to save about half a butterfly's wing in weight. I refuse to confirm or deny that the words "You idiot..." were muttered at the time:
The WSB and other highly spec'd race spec bikes would have this mounted up front behind the dash, to get a bit more weight over the front wheel (it's a pretty sizeable unit, taking up about 2/3rd's the size of an A4 paper in real estate) rather than keep it in the stock location in the "boot". That's too trick for me though, and only God's petrol-head brother knows where you'd find a harness to suit, I'm just happy to have the ECU.
And an electronic tacho, ordered from a contact in the UK. The white faced Corse unit I wanted (to match the temp gauge) is a pretty rare thing and this one was as new, which (groan) means it wasn't cheap. How "not cheap"? Just over $400NZD landed in NZ....except it didn't land in NZ and is missing to this day, bloody thing. No such luck on a refund this time. This is the actual unit in question so if you see it lying around a Post Office somewhere I'd appreciate a shout out....
After a few months with hope leaking out of me like a holed radiator I gave it up as lost and went for the "easy" option of a white face "Ducati" Scitsu instead. It's a quality piece of kit , especially for the price....but nothing smells quite as good as genuine "Ducati Racing".
I've buggered off the bulky anti-vibration mount to tidy up the installation, relying on the dash pod anti-vibration mounts instead. Convieniently in the short term, but probably not so much the long term, it is powered by a rechargable battery so no wiring to worry about other than a signal wire needing to be taped/attached to an HT lead picking up an induced signal.
