Speedometer Calibration
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Not sure if the same applies on Harleys as for Jeeps, but here goes. Jeeps (under Chrysler when mine was made) always have the speedometer showing higher than the actual road speed (about 10% on my '98 TJ). This appears to be deliberate, possibly to avoid litigation from drivers receiving speeding tickets and claiming that their speedo showed they were inside the speed limit.
When driving with an OBD II scanner plugged into the PCM (engine management computer) the scanner was only showing a 1% error against GPS. It is worth noting that it is this signal that feeds the Odometer so even though the speedo is reading high, the mileage is being correctly recorded. I now use a http://www.scangauge.com/products/ as a digital dash, fault code reader and trip computer. I don't know if Harleys have a port you can plug a similar type of scanner into.
Hope that helps.
Woody
When driving with an OBD II scanner plugged into the PCM (engine management computer) the scanner was only showing a 1% error against GPS. It is worth noting that it is this signal that feeds the Odometer so even though the speedo is reading high, the mileage is being correctly recorded. I now use a http://www.scangauge.com/products/ as a digital dash, fault code reader and trip computer. I don't know if Harleys have a port you can plug a similar type of scanner into.
Hope that helps.
Woody
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calibrate, calibration, correction, error, fixing, florence, glide, harley, recalibration, sc, speedo, speedometer, super, tri, tunner