Originally Posted by FastFingers
Well i know some Honda's (especially the motorbikes) are designed to have a false reading to help prevent speeding.
Saying that, 12% is a lot!
I've got a Fireblade and that doesn't over-read! You can get a little box called a "Speedo Healer" that can re-calibrate speedos. It says that it can be used for kit cars, so I suppose that you could use it on any car. See www.mandp.com
. Hope this helps!