| Fitting a push bike trip computer to your Hornet. 
   Well there are a number of reasons. You want a clock. You want an _accurate_ speedo. You want an extra trip meter (odometer). You want an accurate recording of your maximum speed. You may even be sick enough to want to know your average speed, point-to-point. You might _need_ a speedo 'cos some bugger has nicked yours! :-| They make and model that I recommend is the Sigma BC 700 or 800, or even 600. Not all trip computers are equal. The Sigma, and some others, can handle high enough speeds to be useful on a Hornet. The main components are the mounting clip/housing, the actual instrument, which clips on and off the mounting, the sensor unit, which is fixed on the end of wire leading back to the clip/mounting, and the magnet, which is fixed to a point on the wheel, so that the sensor can count the revolutions. For the Hornet, I found that the easiest place to put the magnet was on one of the front wheel's disc brake centres. They have kinda spoke type bits coming out at a slight angle. The magnet that you get as part of the Sigma kit, is a bar magnet enclosed in a black plastic casing. Examine the plastic to establish which side has the bar magnet and which side is just plastic, then, with a sharp knife, cut the just plastic side to an angle approximating the angle of the "spoke" bits of the disc. Now stick the magnet in it's modified casing, onto the spoke of the disc. You can use Araldite, or any other stickness. I used double sided tape, then a quick bit of electrical tape round the outside.....good for 200 kph at least. Now, to fit the sensor, you need some of those nylon, zip-lock cable ties....colour to youre own taste. The sensor has two cut-outs for moun ting, which accept smallish cable ties, so I used three, zipped together sequentially, for the top and three for the bottom mounting cut-outs. The sensor has a rubber backing, so it doesn't slip about. You position the sensor so it is fairly close to where the magnet passes, _before_ you fully tighten the cable ties. Heave back, and towards the side stand, spin the front wheel, and check that there _is_ a reading on the speedo part of the computer. Once you have checked that the sensor is indeed sensing the passage of the magnet, you can tighten up the cable ties. Now you arrange the cable up the fork leg, and mount the clip/mounting. It is held, as in a pushie application, by a supplied rubber ring, hooked onto top and bottom, and round the handlebar tube. If the supplied wire is not long enough, it is not "magic" and you can snip the wire and splice in the requied extra length.  All you now have to do is calibrate it. You need to mark a point, or line, on the front tyre...chalk or coloured tape will do. Then roll the bike forward so that the marked point is exactly at the point of contact with the road/floor, immediately below the axle. Chalk mark the point on the road/floor where this is, then get on the bike and roll it forward, one full front wheel revolution. Again, mark the spot on the road where the marked possie on the tyre contacts, then measure. Note: This has to be quite accurate. The distance that you have measured is the effective rolling circumference, and that is the number you have to put into the computer. The actual set up of the computer is decribed in about 16 different languages, so I won't both you with that here. You should re-calibrate the speedo if you change tyres, but, since it operates on the front wheel, you don't care about gearing changes. Yes, I know it doesn't work if the front wheel is up in the air. ;-) Hope this makes sense... regards, CrazyCam |
