US ECU in a rest-of-the-world 2009?

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I'll be interested to hear whether your speedo is more accurate now. The ROW speedos seem to follow the 10% high Euro guidelines but the USA bikes seem to read accurately.
Interesting question. My bike is ex-police, so the speedo was calibrated to be accurate already.

From taking the dash apart it looks like the calibration was simply replacing the backplate of the speedo with a custom printed one showing a slightly different scale.

I wonder if the USA bikes use the same technique. Next time I'm out I'll compare reported speed to GPS. If there's no change after swapping the ECU then that ought to confirm the accuracy/tolerance is just down to how the speedo's markings are printed.
So the calibrated UK speedo remains accurate after the ECU change, suggesting that all ECUs report the same speed to the dash.

And a very unscientific method suggests that the calibration of speed is purely done by the speedo's backplate. I've compared a US speedo to a calibrated UK one, and as you can see the marks differ slightly. Most noticeable if you look at 130mph - it's left of top-dead-centre on the US speedo, but slightly to the right on mine.

So if you're looking for a more accurate speedo, you could either buy a whole US dash, or get a new backplate printed out (which is how the police over here do their calibration, as you can see in the third image).


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