Trip Computers
Similar (in functionality) to that on the Africa Twin
last update: 21/04/2001
Functionality
Actually it's a bicycle accessory but no problem ! Those "computers" are
supplied by SIGMA, RALEIGH et al. I wouldn't say I was in a desperate need of it.
Actually, I wanted a clock (this is really indispensable), so I thought "why not buy
a trip computer with clock?". My SIGMA BC1200 (about $35) has the following features:
1. Internal battery, no need for external wiring but that for the speed
sensor.
2. Display illumination. When this feature is activated, light is on for
a few seconds only, every time a button is pressed (in order to save the battery).
Update:
recently, this feature seems to be omitted in all SIGMA models.
3. Hourly speed up to 200 Km/h. For accurate results, a wheel
circumference setting is provided. This setting can also be used for achieving a Mph
display. Absolute accuracy is higher than that of the original speedo and it is constant
(not speed depended).
4. Trip distance, 10m accurate.
5. Clock.
6. Stopwatch and total trip time, not counting when vehicle is not
moving.
7. Maximum and average speed.
8. It is waterproof. Operating temperature range is 0-70oC. If
those limits are exceeded, display retains normal functionality when temperature returns
to the operating range.
Installation
The main source of troubles comes from mounting the sensor and magnet. Installing directions supplied with the product suggest mounting the sensor on the fork while the magnet is fitted on a spoke. However, all the above do not apply to any motorcycle, due to the long fork-spokes clearance. It is generally accepted that the magnet must be mounted on the plastic cover inside the brake disk. I think that a good position for the sensor is right on the end of the tachometer cable (see picture below). Since SIGMA sensor (1) consists of two parts (a socket and the actual sensor), mounting it on the speedometer cable does not prevent cable removal. However, in single brake rotor models, this cable is not located on the same side with the disk. In case of single rotor brake model (1987-1996), the sensor installation shown doesn't apply, so you must secure the sensor (using tiers) directly on the other fork.
Magnet can be easily installed on the disk brake internal cover (2) by carefully
drilling a small orthogonal hole on it. If that hole has the appropriate size, magnet will
easily "snap" into it. Then, it must be secured using epoxy glue. Before
drilling, ensure that magnet passes within 0.5cm (max) from the sensor, otherwise
instrument will not operate.
Sensor socket must be supported on the speedo cable using two ties and epoxy glue. Sensor
cable is always shorter than needed, so it must be extended using two-wire flexible cable,
shrinkable insulating tube and a soldering iron. If sensor cable is of the very flexible
telephone type, it cannot be soldered. I didn't had any problem when I soldered the SIGMA
sensor cable. The cable must be secured on the speedo cable (using ties) in a way that
there is no possibility of damaging it when using the handlebar.
I think that the best position for the instrument is on the left side of the handlebar since it is sufficiently near the driver while instrument socket is not easily visible by vandals (the main instrument must be always removed when leaving the bike). If you use a large tank-bag, do not install the socket firmly on the handlebar.
Other info
In order to have proper speed / distance dispaly, you have to adjust its "wheel diameter" setting. If you don't want to bother with tests for maximum accuracy, enter 2130 value (for metric units display). A simple but effective verification method is to compare its odometer (not the tachometer) reading with the motorcycle's odometer.
These units are relatively sensitive to sudden knocks, so be careful no to leave it fall to the ground. Partial damage to the LCD or freeze of function may happen. In the latter case, remove batteries and install them again to perform a device reset.