Speedometer discrepancy

[SpudRider]

Originally Posted by Mudflap

Some electronic speedos can be recalibrated simply by putting them in set-up mode and punching in the correct wheel diameter. May take a 16 year old to figure out how to do it though. Could be as simple as holding down both buttons while turning the key on, but probably not.

I have tried starting the bike while holding down each individual button, and both buttons. Unfortunately, none of these attempts put the speedometer into calibration mode.

Originally Posted by Weldangrind

Interesting. Does that mean the speedometer unit is not connected to the Siemens CPU?

I'm sure the speedometer is connected to the Siemens microprocessor. However, the Siemens VDO Speedometers sold in the United States have one button, and are set up to enter configuration mode as described by Mudflap. The details of the configuration mode for the U.S. units are provided in the two documents I have linked below.

http://www.nsifleet.com/pdf/ProgrammableSpeedometer.pdf

http://www.springfieldstreetrod.com/...ionsSpeedo.htm

[Weldangrind]

I remained convinced that it must be calibratable. I'm hopeful that the talented people here will sort it out.

[SpudRider]

I'm almost inclined to 'bite the bullet,' and get the SpeedoDRD. If someone has a good idea how to calibrate the Siemens CPU, please let me know.

[oldqwerty]

Try turing the key on but not starting the engine, then hold individual and combinations of buttons. I had a compass you had to hold the button down, then power up.

[Huck369]

I have an ideal on a "fix" for this, when I finally get around to trying it out, I'll post back results....

should change from 14% high to about 5% low...so it would read about 53 mph when you were actually doing 55 mph, opposed to the current "reading 62 mph when you are actually doing 55 mph"

[SpudRider]

Originally Posted by oldqwerty

Try turing the key on but not starting the engine, then hold individual and combinations of buttons. I had a compass you had to hold the button down, then power up.

Thanks for the input, but I think I have tried every possible combination of pressing buttons, both while starting the speedometer, and after the speedometer is running. I have performed all these experiments while the engine was not running.

[SpudRider]

Originally Posted by Huck369

I have an ideal on a "fix" for this, when I finally get around to trying it out, I'll post back results....

should change from 14% high to about 5% low...so it would read about 53 mph when you were actually doing 55 mph, opposed to the current "reading 62 mph when you are actually doing 55 mph"

Thank you, but please don't tease us. Would you mind telling me your idea? If not publicly, would you send me a personal message?

[SpudRider]

I'm pretty sure the RX3 employs a 3-wire, Hall Effect sensor. The SpeedoDRD receives this signal, then modifies the output rate to the speedometer, as shown below.



If someone knows of a microchip which performs a stepdown function of about 10 percent, we can build our own speedometer calibration unit. The only benefit of the SpeedoDRD is its ability to program the unit for different size wheels and tires.

[SpudRider]

For example, here is a speedometer calibrator design which employs a $20 microchip, which can be programmed on your computer.

http://members.rennlist.com/tom86951...r%20Page1.html





http://rennlist.com/forums/944-turbo...alibrator.html

[Huck369]

Originally Posted by SpudRider

Thank you, but please don't tease us. Would you mind telling me your idea? If not publicly, would you send me a personal message?

Sending PM......

[SpudRider]

Originally Posted by Huck369

Sending PM......

Thank you, Huck.

[fishman10]

Huck,if you figure it out ,even for just the stock ture size ,I want To purchase one,I really want to know how fat I'm actually going!

[Weldangrind]

Originally Posted by fishman10

I really want to know how fat I'm actually going!

I already know how fat I'm going. Too fat.

[fishman10]

good one weld !!! My laptop is down,, so hitting the buttons on my phone is tuff,, They're small!!

[SpudRider]

Been there, done fat.