Speedometer incorrect speed reading

[Bhlim09]

Hi all , i tried to look around for an answer to my question but couldnt , therefore i am posting this .

I recently bought a 2008 FZ6N S2 , supposed to have ABS but previous owner had “bypassed” the system . All good except for the speedometer , which i understand the readings on the speedo are taken from the ABS sensor . While i was travelling at 100KPH (Satellite speed on phone ) , my speed only shown 58 KPH (not on MPH mode , even lesser speed if i switch to MPH ) .

So one day , remove the front wheel sensor, went for a quick ride , the speedo started showing numbers ,but not when i removes the rear sensor with my front mounted on . So the question is , does the readings on the speedo was actually taken from both sensor or only the rear . Thanks !


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[TownsendsFJR1300]

I believe the speed is taken off a sensor at the back of the engine.

It has nothing to do with ABS

 

[Bhlim09]

I believe the speed is taken off a sensor at the back of the engine.

It has nothing to do with ABS

That was what i thought too , but for ABS model , speed readings are taken off one/both of the ABS sensor .


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[Motogiro]

:welcome: to this great forum!

If the speed is taken off the ABS sensor/s and the ABS has been bypassed it would be the place to start looking for the speedo error. Maybe the system sums the sensors?

 

[Bhlim09]

:welcome: to this great forum!

If the speed is taken off the ABS sensor/s and the ABS has been bypassed it would be the place to start looking for the speedo error. Maybe the system sums the sensors?

That is what i thinks too , my speed do not pop when rear sensor are removed with the front sensor attached .


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[TownsendsFJR1300]

Part #12 is your speed sensor:

 

[Motogiro]

Part #12 is your speed sensor:

Yes this is the speed sensor. I don't know if they did a change on the ABS bikes but if the OP's bike has this sensor as Scott has shown, this will be the first place to look.

 

[TownsendsFJR1300]

Yamaha wouldn't have changed the design/ use of the sensor for the ABS model to include how the speedometer reads.

I'm sure the ECU takes into account the ABS signals from the sensors to activate the ABS but that shouldn't affect his speedometer.

 

[Motogiro]

Yamaha wouldn't have changed the design/ use of the sensor for the ABS model to include how the speedometer reads.

I'm sure the ECU takes into account the ABS signals from the sensors to activate the ABS but that shouldn't affect his speedometer.

https://www.cycleworld.com/sport-rider/how-to-fix-calibrate-inaccurate-motorcycle-speedometer/

There may be changes to the FZ6 we are not aware of as Cycle World mentions that most ABS type bikes use the ABS sensors to calculate speed.

Sent from Moto's Motorola
Does anyone have a service manual with schematic for ABS equipped FZ6…?

 

[TownsendsFJR1300]

From that article:

"Most current motorcycle speedometers use a sensor triggered by the teeth of a transmission gear or a similar dedicated ring or by the slots in an ABS wheel ring".


As you noted, a wiring schematic should show if the ABS is in the loop for ABS equipped bikes.

Being basically a "beginners bike", I have to doubt Yamaha made a change in the speedometer system when it isn't really required.

If someone can post a schematic would be great..

 

[FinalImpact]

Guys and gals, do a www search for "FZ6 service manual, all versions pdf". If it's still out there, it is the motherload of information.

It has all models, all options, all countries!
With schematics too! :bow:

 

[trepetti]

Guys and gals, do a www search for "FZ6 service manual, all versions pdf". If it's still out there, it is the motherload of information.

It has all models, all options, all countries!
With schematics too! :bow:

I have it and it shows that on ABS models, there is no separate speed sensor. I assume that the change is all in software. Makes sense, as for ABS you need to have an accurate speed sensor on each wheel.

 

[TownsendsFJR1300]

I have it and it shows that on ABS models, there is no separate speed sensor. I assume that the change is all in software. Makes sense, as for ABS you need to have an accurate speed sensor on each wheel.

Ok, so the speedometer calculation is the same on both machines.

Is this correct Randy as you already have the PDF(apparently)?

 

[Motogiro]

Ok, so the speedometer calculation is the same on both machines.

Is this correct Randy as you already have the PDF(apparently)?

https://www.600riders.com/forum/fz6-electrical/44702-speed-sensor-abs.html#post485899
http://www.fazerclub.ru/manuals/FZ6/Yamaha_FZ6_2007_ALL_VERSIONS_Service_Manual.pdf

I've been looking at the 2007 ABS and non ABS model component lists and the ABS model does not list a speed sensor. It looks like the ABS models are using the wheel sensors to process the speed. If that's the case there is the benefit that the speed reading of the vehicle would not change when changing sprocket ratios.
The non ABS models do list a speed sensor.