I've had a mechanical Smiths tacho on my Rapide for several years now........It looks nice opposite the 3" speedo on the other side, but in all honesty, I really don't look at it anymore. Once you know what rev's equate to a certain speed, there is no need for it........The gearbox leaks oil now, so I'll probably remove it.......... the electronic ones are nice, but you have to be careful how you wire them up.......use either the small pickup sensor that attaches to one of the HT leads, or the pickup wire that goes to the SWITCHED SIDE OF THE COIL......... not the positive side........This for either electronic or points ignition........it tells you in the instructions what to do.......If you get it wrong you will suffer issues that might cause you a case of chronic depression or similar....... It can fry the ignition coils and many other side affects. The scitsu tacho's work ok........They claim to have a run time of 10 hours on a fully charged battery........They don't suffer vibration too well........Be very careful you buy the right model for your ignition type, as it can be confusing and they won't refund you, only sell you another one........I've had a couple of them on race bikes now........first one worked ok on the twin racer, second one suffered badly from vibration above 6000 rpm, and the needle just went mad all over the place.