The speedo on my 2008 XB12 has always read 5-10mph over the actual speed (as observed on the GPS). Most of the bikes I've owned have done this (some even worse than my Buell). However it would appear that using ECMSpy you can adjust the VSS input and output corrections, which would potentially correct the speedo?

http://www.ecmspy.com/cgi-bin/detail.cgi?ecm=50&offset=744

http://www.ecmspy.com/cgi-bin/detail.cgi?ecm=50&offset=746

Has anyone tried this? It looks like something that would be good for people messing around with gearing changes too.

My current settings are shown below

It looks like I may be the first to have considered this, so I've compared a 2008 XB9 EEPROM to a 2008 XB12 EEPROM to see what the difference is in the VSS scaling. I believe the XB9 has a 34 tooth front sprocket and the XB12 a 38 tooth front sprocket. The difference in the EEPROM is in the output scaling not the input scaling (XB9 appears to be 5% lower than XB12). So given my speedo reads 10% high, my theory is that reducing my VSS output scaling by 10% should correct this?

Table detailing analysis of EEPROMS:

The pulleys are the same on the 9 and the 12, the primary sprocket is different but all that does is change the RPM to speed relationship. The speed is measured on the 5th gear on both, and since everything is the same downstream (even from the clutch and beyond) the calibration data should be the same.

Be interesting to know whether one is kph and the other mph, obviously not the conversion but to align the needle with the scale.

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08 Specialized Langster

I thought the calibration for mph/kph was in the speedo face printing, the pulses sent from the VSS will be the same in either case? The XB9 and XB12 EEPROMs I looked at were both US ones so I'd say the bikes would have mph speedo for sure.
Interestingly the 1125cr and 1125r VSS settings differ on the input side not the output side like the XB?