I don't think the speedo error is 1000 or 650 specific hence I post here.
This post is intented NOT to start a discussion about if the speedo error is to correct and how, so please do not reply the different solutions!
There are several ways to check how far the indicated speed is from the reality. But what I post here I guess is uncommon.
One of our club fellow is a developer of an instrument which is officially used by cops here to measure vehicle speed. They recently came out with a new version and he took it for a test.
We found a quite long (more than 2 kms), straigth, deserted road.
He installed the unit in the middle of the road-track so he could shot in both directions. One of the end stood my SO with a PMR in case a car comes by chance.
We rode one-by-one. When reached a certain speed I switched on the emergency lights so later on the video I could easily compare it with the measured value which is projected to the screen.
My speedo error is +6.56 %.
I tested the top speed as well. Although the distance I could accelerate was not too long it surprised me.
I tested my SO's CBF 250 also: 80+ Kg load slows her pretty well
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