n da zone
Expert Class
Posts: 215
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posted February 27, 2004 04:49 PM
 Edited By: n da zone on 27 Feb 2004 17:08
Add a cool new toy to your cockpit!
Our bike speedos (and I don't mean your underwear!) can be off by as much as 5% - 10% , and when you add in the changes we make in sprockets and tires, there's no telling how fast you really are going until one of our peace officers decides to stop you and tell you.
One solution for this problem is to install a bicycle computer. (These are advertised to be 99.9% accurate.) I got a Sigma Sport BC1600 computer for Christmas and put it on this weekend. This little jewel has the following features:
Current Speed
Clock
Stopwatch
Trip Distance
Total distance
Trip Riding Time
Maximum Speed
Average Speed
Permanent comparison of actual & average speed
It is about $26 delivered to your door. This is the best one on the market for use on motorcycles . This particular model , unlike most bicycle computers, will record triple-digit speeds (up to about 180mph). Most only go to 80 or so.
The only drawback to me is that it is NOT backlit, so you cannot use it in the dark. Oh well ... not a big issue for me, since I don't do a lot of speeding around in the dark.
All the bicycle computers have three main modules; the display, a sensor, and a magnet. (picture #1)
The sensor, mounted on the front fork, connects to the display/computer by a thin wire. (There are wireless bicycle computers available on the market today, but they require a clean line of site from the sensor to the pickup (display/computer), and have a maximum distance they can transmit.) The basic concept is that every time the magnet passes close to the sensor, another "count" is sent to the display where it is registered. The display/computer then calculates and displays your speed, as well as the other functions mentioned above.
I made a few slight modifications from the 'bicycle' instructions to fit the computer on my ZX12.
1) the wire that connects the sensor to the computer needs to be lengthened
2.) a different magnet was used to mount to the brake disk.
The best that I found locally is something called a Rare-Earth Super magnet available at Radio Shack, part # 64-1895. (picture #2) . Very strong, these little puppies ..... and less than $2 for a pack of 2.
I attached them to the brake rotor using a very, very small dab of super glue. It has not come off yet, and I have been well in to the triple digits with it (picture #3) . Of course the magnets need to be stuck on the rotor, as the spokes are aluminum ...
Don't place the magnet so it passes the center of the pickup - there is a dead spot right in the center. Drove me nuts because I was trying to be very precise and get it in the middle ... aarrrrgghh!
Attaching the sensor was a fun little project. The pack comes with little elastic bands (think o-rings) to use. I chose to build a metal plate that attached under the Kawasaki fender bolts to screw the sensor into. (picture #4) . It was cut from some thin aluminum (18 gauge), using the template you designed in the prior step. (picture #5) . I then mounted the pickup on the aluminum plate. I used a couple of very small #4 screws/nuts to secure the sensor to the plate. (picture #6) .
As for installing the actual display/computer, you may need to be creative to pick a suitable location. (picture #7) . I wanted it up high, in my line of sight, and not down in the standard 'handlebar' location. I made a small bracket from aluminum and used the rearview mirror mounting bolts to attach the bracket inside the cockpit of the bike. (picture # 8) . The final view from the seat is here (picture #10) .
I had to add about 2 feet of wire to the unit. Best to solder all connections to ensure nothing comes apart later. (picture #9) . I used the brake lines as a guide for routing the wire up from the wheel to the instrument area. Make sure that the wires will not bind, stretch or pull when braking or turning. (picture #11) .
After the unit has been installed and tested to be sure the sensor is picking up the magnet as it passes by at each rotation, you will need to "program" the display unit. You are essentially telling the computer how many millimeters around your tire is. There are two easy ways to get this rollout measurement (circumference) ...
1) Get out your "millimeter" tape measure you bought the last time you visited Vienna
...OR...
2). Wrap a piece of masking tape around the center of your tire. Make a starting and ending mark on the tape (they should be touching, but at different ends of the tape.) Take the tape off the tire and measure it. This is the circumference measurement you will use for the setting.
Then, 'Ask Jeeves' to find a formula to convert inches to millimeters and key it in.
Some people will want to take periodic measurements as their tires wear. This way, they can reset their circumference setting to allow for tire wear and thus, a smaller tire size. (can you say anal-retentive?)
Anyway, it allows you to keep track of the average and max speeds, and the speedo is easy to read, big digital numbers, and accurate. Another cool feature is that the computer is 'detachable' from the mount, so when you walk away from the bike, you can slip the computer into your pocket and have a watch to keep track of the time.
--Mark-- 
  
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frEEk
Administrator
ummm... yeah
Posts: 9660
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posted February 27, 2004 10:18 PM
great writeup, thanks. i need to do this very soon myself as i have NO guages right now, and it's driving me nuts.
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redelk
Moderator
Please... speak to the hand.
Posts: 3212
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posted February 28, 2004 01:04 AM
Have used Sigmas for years and haven't looked at a stock speedo since. Started off with a BC700 on my 7R and used a Targa on my 12R. Features like riding time and trip riding time sound nice. So does the settable trip segment. Features the Targa does not have. It will be one of the first accessories I get for the 10R.
I've used the same magnets from Radio Shack. I just put two on my rotor instead of one (entering in half the tire circumfrence) and found that at least for the Targa, it helped in keeping accurate readings when going over 130 mph. Probably wount be a problem with the BC1600. Nice set up.
____________
There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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claude
Expert Class
Posts: 205
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posted February 28, 2004 05:00 AM
How do you know if a precise model of computer is able to handle higher speeds? I looked at Sigma's website and top speed is not part of the specs lists.
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ozzy
Needs a job
need guberment cheese
Posts: 3172
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posted February 28, 2004 07:37 AM
search the web, there is a page out there that describes using a led to back light sigma speedo's.
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slug
Pro
Out in search of my mind...
Posts: 1433
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posted February 28, 2004 08:08 AM
the older bc800 will go as fast as well
i built a bracket out of aluminum tubing and ran wires through it for a LED to shine at night
hardly use it at night though, i still can do themath for the stock speedo ;P
the bracket is going to get changed this month as well, i'm going to tap a hole in the back of the triple tree for a new one that is smaller and less obtrusive
  
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claude
Expert Class
Posts: 205
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posted February 28, 2004 04:17 PM
quote:
...for a new one that is smaller and less obtrusive
Slug, which one is smaller and less obtrusive?
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slug
Pro
Out in search of my mind...
Posts: 1433
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posted February 28, 2004 05:55 PM
thenew bracket will be
the speedo will be in same place, but the bracket will bolt directly under where it is sitting
i will probably ditch the light altogether
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slug
Pro
Out in search of my mind...
Posts: 1433
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posted February 29, 2004 07:43 PM
Edited By: slug on 29 Feb 2004 19:45
new bracket
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