Anyone know what the "reed switch" does on the speedometer

engine22 · Full Member Joined: Apr 10, 2008 Posts: 104

I recently purchased a used speedometer and the reed switch hookup is not compatible with my bike. It could easily be modified, but just out of curiousity I tried operating it without the reed switch hooked up and it seems to function completely normal. Anyone know what this does? Is it even necessary?

I know its a pretty common piece of electrical equipment but could not find how it would function in a cable driven speedometer. I did, however read somewhere that even though its in the speedometer it might function as part of the turn signal self-cancellation system, which hasn't worked in a long time on my bike anyways, so that would be no big deal..

acbanks

A reed switch is basically a magnetic switch. Two thin reeds of metal in a sealed little glass tube. When you bring a magnet nearby it closes. I'm using one for the bicycle speedo I'm running right now. In my case I have a magnet on the brake rotor and the speedo counts the times the magnet goes by.

pamcopete

engine22,

The reed switch sends distance pulses to the turn signal self cancelling unit. Totally useless. Most people just remove the self cancelling unit.

xjwmx

A turn signal that's left on is an invitation for somebody to pull out in front of you. But no prob. Just send Pete your medical bill Wink

pamcopete

xjwmx,

Well, some people think that the self cancelling unit is a great and simple device but it gets a little more complicated than that.

From the Haynes manual, page 162, (28):

“The purpose of this system is to turn off the turn signal automatically after a period of TIME or DISTANCE. At very low speed, the signal will cancel after a distance of 164 yards has been covered. At high speeds the signal will cancel after a time of 10 seconds has elapsed. When traveling in the lower range of speeds the signal will cancel after a COMBINATION of both time and distance.”

Yea...right...I think that the phase of the moon has something to do with it as well.

When I first got my '78/E, I didn't even know it had a self canceling feature. I just noticed that the turn signal seemed to be intermittent and would stop working at the damndest times.

So after I had my close encounter making a left turn in front of the the beer truck when the turn signal cancelled (to this day, I won’t drink Budweiser!) I pedaled on home determined to fix the intermittent turn signal before I got killed. As I rummaged through the wiring and my Clymer manual crude wiring diagrams, it suddenly dawned on me that the damn turn signals were cutting off DELIBERATLY!! Soon after, I located the canceling unit and ripped it out of the bike and hurled it across the garage......

Now, more than a few years later, I bought my "new" '81/H and it still had the canceller installed. So, I thought, I'll give it a chance.The wiring was in excellent condition...like right from the factory, so I wanted to maintain the pristine stock wiring.

It didn't take long, however, for the game to begin. Me against the canceller. Can I complete this turn before "it" decides my times up? Am I ok with constantly having to look down at the blinking light when I'm in a busy intersection? Do I find myself rushing to complete a turn before the turn signal cancels?

So, without further ceremony, I removed the canceller from my '81/H, thus ruining it's factory, pristine wiring.....and I'm happy again.....I can take my good old time completing that left turn...I no longer have a referee riding with me, ready to blow the whistle for taking too much time.

I also think that with the canceller, you have a tendancy to let it dictate when and where you will operate the turn signal because you know its going to cancel. In my case, I found myself rushing to complete the turn before it cancelled....not a good way to see the next day.

So, basically, if you can't remember to cancel your turn signal, then you shouldn't be riding a motorcycle. If you haven't noticed the randomness of the self cancellor, then you have not been paying attention, and shouldn't be riding a motorcycle. Take a taxi before you hurt yourself.

And...motorcycle accidents are generally fatal, so there would be no bill to send.

xjwmx

Never advise removal of a factory installed safety device. An opinion that anyone it might benefit shouldn't be riding won't save you.

Heck, the canceller you took off might have even benefited you someday. We know you've never left a turn signal on before, but there's always a first time. By the way, thumbing the signal a second time resets the "count" if you need it on longer.

penn71911

"Most people just remove the self cancelling unit."

That doesn't sound like advice... sounds like a statement to me...

y self cancelling unit is long gone... bump the switch, make the turn, bump the switch... just another learned behavior.

Hell... the cagers don't see me anyway... like they'll really see my turn signal...

pumps · Last edited by pumps on September 10, 2009, 12:28 pm; edited 1 time in total

Removed mine. My other bike doesn't have one. I'm pretty good about shutting it off. There's a pretty easy audible signal mod out there that is easy to wire up if you like to know by hearing if it is on or off . You could leave it whichever way you like. You'd just hear if it was on. Google motorcycle turn signal audible mod or something. JC Whitney even has a two prong audible flasher relay for cars that would probably work , just plug and play.
www.jcwhitney.com/auto...urn+signal

Found another.
www.turnalarm.com/

JeffM

Honda used to put an audible signal on their turn signals, annoying at a stop... so of course most people just remove them!! lol

What Happened to 650rider.com?

Yamaha xs650