Installing a cycle computer on bikes

[noobie]

Hello people.

I've got a question for you. I've seen many times supersports bikes having those bicycle digital computers installed (Sigma, etc,...), they even sell them at motorcycle shops where I live.

But how the heck do I install one on a motorcycle?

Bought one of these a few years back for my Yammer Virago, but even though the bike has spoked wheels (like a bicycle) couldn't find a way to put the transmitter on the spokes and at the same time close enough to the receiver on the fork so it could send data.

In the end I gave up and decided to replace the old one on my road racing bicycle with this new one and scrapped the whole project.

But now I'm at this point again. I'm about to seriously get to restoring my GS1k after I've had it for 4 months. The restoration of my little Honda CB250N had had priority. Something I now dearly regret, cause I could've been riding the GS the whole summer and instead I now have to ride a kiddie's bike (just 250 cc and 27 HP) when I could be riding a real man bike. But, since the bike is smaller I foollishly thought it would be done sooner.

But now I did a long trek with the 250 to the coast and anew got the determination to install the cycle computers on ALL of my bikes cause the 250's speedo shows 10-20 mph faster than the actual speed. No wonder those damn RVs were glued to my ass and tried to force me to ride faster... lol.

Then I had to speed up at least 20 over my shown speed in order to ride according to the speed limit. Which left me scared of speed traps cause I didn't know what my exact speed was.

So I decided I need the cycle computer on the 250 and on the GS.

Anyone have any idea on how to install them on bikes with mag-type wheels? Photos of how it looks like would be much appreciated!

Btw., the GS's break disks are the ones without any holes so I can't even put disk locks on it.

Thanks and looking forward to your replies!

Noob

[Smokinapankake]

Try wireless? Don't know if the engine/electrics will cause any RF interference, though. I like the idea as well because my 84 Kat speedo displays only in Km's.

[noobie]

Try wireless? Don't know if the engine/electrics will cause any RF interference, though. I like the idea as well because my 84 Kat speedo displays only in Km's.

Actually the cable is not the problem, the problem is that there has to be a distance of only about 4-5 mm between the magnet thing on the spokes and the sensor on the fork.

I guess I didn't explain right.

My problem is not the distance between the display and the fork, but the distance between the magnet thingy that goes on the spokes that is then registered by the sensor mounted on the fork. The computer then senses the times the magnet thingy moved past the sensor and according to the provided circumference of the wheel it calculates the speed of the front wheel.

The problem I have is that I can't figure out how to mount the sensor on the fork close enough to the magnet, cause the magnet is way farther from the sensor than just 5 mm. More like 50 mm.

And now that I have mag-type wheeled-bike I now have even more problems: how do I attach the magnet to the alu wheels in addition to installing the sensor close enough, sinse the magnet was made for spokes...

[Matchless]

Never done this but it should be possible.
The little bit that goes on the spokes is just a magnet, that generates a puls in the pickup on every turn.
Make a small bracket so that the pickup is as close to the outer rim of the wheel. maybe use on of the front fender mounting bolts. Just tape the magnet to the inside of the rim and turn the wheel and see if it works. Then try a small flat magnet that can be stuck to the rim in the same way as some wheel balancing weights. As the wheel spins the centrifical force will push it against the inside of the rim, so it should easily stay there. Let us know if it works with pictures as this sounds like a good idea.

[noobie]

That's a great idea, thanks. But I see a possible problem with that: in the computer manual it says that the magnet should be installed around the middle of the length of the spoke to give most accurate speed reading. The thing I'm asking myself is, just how much will this longer interval between pulses influence the speed readout.

[Matchless]

That's a great idea, thanks. But I see a possible problem with that: in the computer manual it says that the magnet should be installed around the middle of the length of the spoke to give most accurate speed reading. The thing I'm asking myself is, just how much will this longer interval between pulses influence the speed readout.

As I said try it by just taping it up temporary. You can spin the frontwheel with your hand to see if it is indicating anything. Basicaly you will not know until you try it. If it sees the pulses you are 50 % there. If it is possible to set the calibration to show the proper distance and if the device can display 3 digit speeds (not sure if a bicycle speedo can go above 99 MPH!) then the chances are good it should work.
Good luck.

[Ed Vrolijk]

Hi Noobie,
I have the sigma targa on my GS1000, and below you'll find some pictures of how i installed the magnet and the pick up sensor.
The pick up sensor is the thing on the metal wire thing.




Succes,
Ed

[8trackmind]

Sigma BC800

My pickup is mounted to the speedometer cable. The wire for the pickup is attached to the speedo cable as well.
The magnet for the pickup is glued to the brake rotor. Works great.



And yes, most of the bike speedos will read above 99mph. Mine goes to something absurd like 188mph, but I've only had it to 120.

[Ed Vrolijk]

My pickup is mounted to the speedometer cable. The wire for the pickup is attached to the speedo cable as well.
The magnet for the pickup is glued to the brake rotor. Works great.

Isn't the idea behind the bike speedo to do away with the original speedo and cable?
On my set up the pick up and magnet are mounted aprox. 10 centimeter from the center of the wheel, but it works great. (at least i hadn't had a speding ticket since i installed it )

[noobie]

Wow, thank you very much for your help, guys, and especially thanks to Ed Vrolijk for the pics.

[hampshirehog]

Ed - that's a blindingly obvious place to mount things - smart and tidy. Why didn't I think of that? Next time I do one that's where it's going.

[Matchless]

I repeat what hampshiredog said! I also never thought that it could go on the disk.
Ed, can you give us a picture of the magnet mount if possible

[8trackmind]

Isn't the idea behind the bike speedo to do away with the original speedo and cable?

I kept it for the odometer, and to keep up with total mileage. It's actually pretty accurate, but the speedometer isn't.

[Planecrazy]

My unit only goes to 99mph (not normally an issue for me), but because I epoxied (glued) my magnet to the outer rim it DOES pass the sensor too fast to get an accurate reading above 74mph. I mounted the sensor itself on a custom "tin" bracket that bolted to one of the fender bolts, but I have to say I REALLY like the pics above using the rotor as a magnet point and a stiff wire to mount the sensor - very slick. I plan to duplicate that, but will have to extend the sensor wire to reach that point on the wheel (the reason I originally mounted mine where I did).

As to why I originally went with the bike computer, my original speedo/tach registered speed correctly, but the odometer wasn't clicking off the miles correctly - I'd get 2/3rds of a mile for each actual mile I travelled. I also liked the trip computer and other features the bike computer offered, so that was the original motivation for adding it, as well as the accuracy of the digital unit (which I found was excellent using the gps to compare). I've since replaced the speedo with one that functions properly, and also use a GPS on the bike which gives me the other computer functions. Although the bike computer is still on the bike I rarely reference it anymore except for the digital clock - nice to be able to see the time at a glance!

Regards,

[Ed Vrolijk]

Well, thanks guys. You can see the magnet in the first picture, almost touching the pick up. be sure to mount it close to the centre of the disk, otherwise it will hit the calliper.
So far i never had problems with the bike speedo. The only thing that happens under fast acceleration (as in throttle as far open as possible in any gear) that the reading stands still untill you reach a more steady speed, wher it picks up again. one moment it reads 45, the next it tells you 180 (KM of course )
Ed