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GSXR Front End : Speedo Conversion II

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36K views 159 replies 48 participants last post by  Newt  
#1 · (Edited)
Jim's Speedo Conversion
Newton's Speedo Conversion preview

Jim's speedo conversion is very nice and does the trick. THe sensor selected is rugged and sensitive enough to pick up a pretty small magnetic field.
However, I found a couple things about it, that for my purposes, needed some changes.
1) I don't like the big sensor
2) or the big magnets and their mounting location
3) You can only tell the sensor is working while mounted with a meter or spinning the wheel.

To make it fit my needs a little better, I picked a different sensor. Almost anything that will operate within your electrical system peak voltages and sources a digital signal should suffice.

SENSOR SELECTION
Comtronics limit sensors. I don't feel like running out and getting the model right now. They are made for pneumatic piston/machine part limit sensing in industrial applications. Plenty tough.
They are smaller and more sensitive, and have a built-in LED so you know it's active. This allowed me to place it farther from magnets (or use smaller ones), and hide it behind the fender. Also, since I have 3 of them, I got a couple spares on hand just in case.
On the down side, they are not intended for automotive use, so are not totally sealed and probably not rated to auto grade. I brushed them with a little enamel paint, should be OK.
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SIZE COMPARE
As you can see, the new one is considerably smaller, and that is after I totally shaved down the other sensor.
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ON/OFF STATE DETECT
Easy-peasy; green light off, green light on. Note the much smaller magnets.
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MAGNET PLACEMENT
Because they are small, I decided to mount the magnets IN the rotor. An added benefit: because they are closer to the axle, they have a greater included angle in terms of wheel rotation = longer detection time per magnet width). Not shown, but I measured out the magnets to fall directly under one of the fender mounting bolts as the rotor turned. The are spaced on every other arm - 4 magnets evenly spaced.
Here I am cutting holes to sink them into the rotor - milling bit in the drill press. A real drill bit will make the bottom of the hole conical, so don't do that. I made them stick out just a hair: flush would be good too, but I figured a little edge might help me dig them out later.
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A BIT OF ADVICE
Get that old loctite out of there. Dressing threads is sometimes a good idea anyway.
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I think everyone should see this. ;D
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ROTOR BACK ON THE BIKE - MAGNET POSITION
The magnet hole is about to pass just behind that fender mount. THe sensor will hang from a mount on the other side of the fender, hidden from view.
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MAGNET ATTACH
2-part epoxy the 4 magnets around rotor, and clamp down until cured. They are almost, but not quite, flush with the rotor. Binder clips are great for this kind of thing.
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CONCEALING EVIDENCE OF THE CRIME
Hide the magnets with some black nail polish. I love that stuff - I always keep some in the toolbox. That may be a crime in and of itself.
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Hide the wire behind the brake lines. Clamp on the lower triple and cable tie on the brake line itself keeps the wire tidy and out of view.
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HELP OFFERED FROM NEIGHBOUR
Appreciated, but without opposable thumbs, you'll just get in the way. Come back for dinner. ;)
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#2 ·
Before I forget...If want to do this, dont' cross the wires: you will smoke the sensor.
Brown = Vsupply
Blue = ground
Black = signal


To mate with the OEM harness...
Brown -> Orange
Blue -> Black/White
Black -> Pink
Image
 
#14 ·
I can't get the camera in there to see it; I'd have to take the fender off. That's the point.

For testing purposes, I velcroed it to the fork leg. That might have lasted a long time, but I only kept it for a week.

After that, I made a little aluminum bracket, cut holes to mount and run wire, ran a longer bolt through the fender mount, and secured it with a nut on the reverse side. A little rubber washer action keeps it from scratching the fender mount. Because it's so small and light (and I cut the bracket to be rigid) I think there is no vibration or flex to speak of.
 
#13 ·
Here's the sheet on them. make sure to get the sourcing outputs, not sinking.
http://www.compactautomation.com/pdf/sensors.pdf


Another note:
These little boogers are sensitive. You can get two triggers per magnet if you orient it correctly and close enough; you can get away with just two magnets, but the placement would be more critical. If your speedo reads twice what it should, this is likely the culprit - move the sensor so the magnet passes more by the head, instead of across the whole unit.
 
#27 ·
Yep..that is what it looks like, although not so new and nice.

BTW...I was just looking at some metal supply sites....1/2" 6061..enough to do a triple...about $194. Egay here I come.
 
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#28 ·
DougZ said:
Yep..that is what it looks like, although not so new and nice.

BTW...I was just looking at some metal supply sites....1/2" 6061..enough to do a triple...about $194. Egay here I come.
Click to expand...

how big a piece ya need??
 
#36 ·
I was thinking... Could one also go about mounting the speed sensor to the front sprocket? But instead of 4 magnets only use 1 magnet? Then in conjuction with a speedo healer it should work right?

Also, I am trying to find a smaller sensor myself. I just don't know what specifications to look for. Can someone chime in perhaps?
 
#37 ·
Give yourself enough margin on the power supply side: 12VDC is not enough. I personally wouldn't use less than double, i.e., 25VDC. (These are 24: close enough).

Then there's operating conditions. The one I used looks like it 's guaranteed to work from 0-70C. If you can get sub-freezing to 70C you're covered across the board.

Signal output, I never actually tried to figure out the load at the instrument cluster. Since they are high impedance I didn't worry about it - current draw will be negligible.

Look at these specs. Stay with them and you should be OK.http://www.compactautomation.com/pdf/sensors.pdf
 
#41 ·
Before I forget...If want to do this, dont' cross the wires: you will smoke the sensor.
Brown = Vsupply
Blue = ground
Black = signal


To mate with the OEM harness...
Brown -> Orange
Blue -> Black/White
Black -> Pink

But, based on this from page one...if one were to try it...it would go like this:

650 harness ....1K sensor
pink......pink white stripe(blue on actual sensor)
black/white...black/white( same for sensor)
orange.......orange/red( brown/red on sensor)


:D Does that muddy the waters even more.
 
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#44 ·
hmm alright. I think I will run it off my rear wheel, as I am going to have the entire rear end (including swingarm) off the bike, I can run the cable where it can't be seen. I think I will use the rear brake as my mount for the speedo. All I need then is a healer to make the speedo spot on perfect (I hate that its off).
 
#57 · (Edited)
fms1day said:
Hey i was wondering if you can dig up the part number to the limit sensor you used for the speedo.. and also where you got the magnets..

I found a distributor of the limit sensor but they couldnt tell the part number from your picture and said it'd be best if i provide them with a part number for the item

thanks in advance!
Click to expand...
Posting here so everyone can get the info.

part# = WSCP
magnets = courtesy of Radio Shack. ;D



FYI, there are 6 varieties of this sensor:
Current sourcing:
WSC, WSC-3, WSCP

Current sinking: do not get these
WSK, WSK-3, WSKP
 
#61 ·
Honeslty I don't know the actual physical reason - different orientation/size/properties of the semiconductor material used for the Hall Effect? Thinner housing (i.e., the magnet is closer) maybe?

In any case, it's a property of the sensor.
 
#62 ·
So the only way to tell is to just use it and see via trial and error? I'm just curious since you mentioned how any sensor with the right properties will work. I'd be interested to find one that is a bit more rugged since I ride in the rain and stronger is better so I was just trying to see how I would know its relative strength.

Oh well, this still helps a lot. Thanks!

D
 
#63 · (Edited)
Use the one Jim sourced, or else ruggedize this one. I coated mine and I'm pretty confident it will be fine. I've used these same units as electronic ignition triggers on a bike for over 2 years with no issue, much of that time with the cover off. They can take it.

As far as sensitivity, you'll have to scour the datasheets. But, unless you know what you're triggering from, i.e., how strong the magnet is, it wont' make a lot of sense to you. I suppose jsut comparing the numbers between all of them would give you the most sensitive of the lot.

I wouldn't worry about it. The big one from Cherry and the Comtronic both work great - I tried them both. And in all seriousness, almost anything will work - this isn't a high precision application. If you dont like how close you have to put it to the rotor, get stronger magnets.

No need to overthink this one; just do it!
 
#64 · (Edited)
See those two brown things? They are pieces of plastic holding two of exact same sensors over a wheel with a magnet in it to trigger the ignition. Matter of fact, one of those two IS my speedo sensor now (and that pic is about 8 years old). This was ridden in the rain, dusty desert, got splattered with all manner of funk and worked 100%. (take that contact points!). They are very accurate/repeatable, far more than you would ever need for a speedo.

Dey be helluva tuff.

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