Mine matched both my Garmin 665 and every police speed box I have ever passed.
My speedometer is dead even with the GPS. Tested it at different speeds up to 85 mph.
At 100 kph on the speedo my gps says 95 kph. I just adjust in my head.
That's either quite a coincidence, or something truly awry with the hoser bikes
Ay?
My 2006 1300R VTX was off. Riding 45 mph, people were always on my butt. Well, every speed unless I thought I was speeding. My GPS showed what speed I was actually doing. I purchased the Speed O Healer. Easy to install. It connects plug & play. It's cable has a little digital box and a set button. By their website, you type in the information and it gives you a number to dial in. Now I am on the money. Also, the Odometer does not rack up miles faster than I am traveling them anymore. I was able to do my brother's 1300C in under 15 minutes in the parking lot of his work.
My Honda 750 and 1300 were off about the same.