Triumph Rat Motorcycle Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter #1
Hi there, I'm looking for more info on the speedommeter sensor of a Daytona 955i 2003, I almost got my rail running, yep a 955i in a mini sand rail, and it's time to hook up the speed sensor, since I can"t use the original I need to find a way to duplicate the signal from the sensor from the front wheel, I took a very close lokk at it and it appear to be a Hall Effect sensor, one wire is the negative ( black, one come from the ECU and the other go the gauge.
I need any information related to this device.
I still work on a way to read the code of the ECU with some specialize engineer at work.
 

·
Registered
Joined
·
165 Posts
A member( DEcosse )
bought a sensor from Acumen.
He sent me a message and this is a quote from it

According to the Acumen guy, he said the "early Triumphs with Sagem ECU" have a 4 pulse per rev sensor & explained that is why the shift time is slow response on the Triumphs - if that is indeed the case, you would use the Acumen with 4 magnets & it should be the same as the OEM.


Maybe thats what you need for your project?
Mikey
 

·
Registered
Joined
·
25 Posts
Discussion Starter #3
Mikey, you may give me some indication, the magnet is one piece with one openning, so I guess it's on ( signal) all the time except when passing over the openning, no signal ( they may encode reverse) , anyway, If I could know what kind of signal to look for I may be able to install an another sensor..... and be able to read the speed out of the original dashboard :)
 

·
Super Moderator
Joined
·
21,826 Posts
It is indeed a digital type signal that pulses as the wheel revolves - these are always hall effect /inductively coupled and generate an emf (voltage) that is induced by the electrical field changing due to a magnet or metal object passing through the field.
Now these devices all have three wires - power, ground & the O/P which is the one that pulses. You can typically replace any sensor with one from another vendor as the electronics in the speedo has a buffer that normalizes the voltage required for the circuitry.
The trick to matching is not so much in the magnitude of the voltage of the pulse that is generated, but in equating how many pulses per revolution there are between OEM & the aftermarket device utilized.
Now most after-market speedo's all have built-in calibration circuits so you can accommodate different number of input pulses per rev but the OEM gauge is fixed, so it's important to know how many pulses are generated in a single revolution of the front wheel by the OEM sensor
Also recognize that if you install a sensor on the rear wheel drive, it will be a different calibration because one revolution of the back wheel is different distance to one of the front, due to the different tire sizes. However you can install one of the after-market calibration devices to accommodate that fairly small difference (however they won't accomodate a substantial difference in number of pulses, like 2x or greater, more like maybe 50% max)

If indeed the OEM front wheel sensor is 4 per rev, (I don't absolutely know this for sure) then you can use any number of available after-market sensors on the rear wheel and utilize 4 trigger magnets then add the cal device (like Speedohealer or YellowBox) to fine tune it.

The key question is if the OEM is really 4 pulses per rev!
Is there any way to tell from looking inside the device?
Ideally you stick an o'scope of the O/put & just see how many pulses you detect in a revolution of the wheel. I'm not sure if you'll be able to see it with just a digital meter but you could try.

If I could temporarily get hold of a digital speedo or OEMsender, I be happy to test it out for the greater good.
 

·
Registered
Joined
·
1,531 Posts
I don't know if this will help but the magnet that is inside the speedo housing is circular and I'm pretty sure it's magnetized like taking two horseshoe magnets and welding them together to make a circle. Does that make any sense? It's magnetized so the N/S is split through the center line of the center hole so I think the magnet is a N/S and N/S again. I haven't got it out to double check it. I wonder if that would make for 2 or 4 pulses? My guess is 2.

:???:

To be perfectly honest I wouldn't use the Triumph housing setup for your application. The magnet is very brittle and breaks easily. There is no bearing of any kind between the magnet ring and the plastic housing. Only a thin layer of grease keeps it from seizing. Probably not a robust enough setup for a 'Sand rail'! i would make the sensor from individual parts like DEcosse mentioned. A Hall effect sensor (like used in a crank trigger ignition and mount some small magnets or make your self a wheel with the necessary cuts or notches for your application. That would be much more bullet Proof for a dusty, abusive environment like you are planning.
JMHO!
:-D
 

·
Super Moderator
Joined
·
21,826 Posts
There are quite a few commercial options available that come as a kit with wiring, connectors etc
For example, you can use the Acumen one I used with mounting details in this thread - Procycle Digital Speedometer Retrofit

That was the drive for the Acumen Digital Gear indicator which is actually available separately. I actually used the single sender to drive both the gear indicator & the speedo together. Other options would be the Veypor drive kit (only comes with one magnet but easy enough to add more) or options from Dakota digital if you care to do a search on those.
It sounds like you should be safe enough in using one of these per the info from Stlakid and then just playing with the number of sensor magnets (either 2 or 4) to see what gives close to calibration. Then add one of these Yellow box calibration devices in-line to fine trim it for determoned accuracy.
YellowBox

[ This message was edited by: DEcosse on 2006-12-09 13:52 ]
 

·
Registered
Joined
·
25 Posts
Discussion Starter #8
delight full info, Gonna try the scope and see what come out.
For the calibration I plan to put the target on a disc with a slot and move the sensor up or down to match the data from the gps, I know all the ratio, front wheel size versus existing new ration, jackshaft and new tire size, I keep you posted of my find.
And Yes, using the OEM doesn't excite me, look flemsy and the way the sensor work....hope you guys do have to much trouble with it..
Merry Xmas :wink:
 

·
Super Moderator
Joined
·
21,826 Posts
On 2006-12-09 21:04, buggyto wrote:
.... For the calibration I plan to put the target on a disc with a slot and move the sensor up or down ....
:???:

Not sure if I'm mis-understanding you or you're mis-understanding how it works:
The effective diameter of the sensor/trigger is inconsequential - it will give 'x' number of counts per wheel rotation depending on how many trigger magnets you use - doesn't matter where they are located on the wheel or any part of the rotating assembly. The effect of the wheel diameter however will affect the net calibration on the speedo itself. You cannot compensate for this difference by moving the sensor/trigger - the number of counts per revolution will remain the same. That's why you use the Yellowbox, to give you a % change that is not achived by a whole number count of trigger magnets (i.e. - if you used 4 magnets & were 20% slow, you would add one more magnet & be correct; however if you were something like 8% or 13% or 24% fast or slow, only way to compensate is to have the yellowbox adjust for it.)


[ This message was edited by: DEcosse on 2006-12-10 00:46 ]
 
1 - 9 of 9 Posts
Top