KymcoForum.com

It is certainly possible to adjust the speedometer, but then the odometer will receive false readings.
In Germany this would be an offense! (Too many dealers manipulated the odometer to cheat the customers.)

Well, to my experience in the automotive industr, today most speedo's are adjustable.  It's due to the fact that varying tire sizes quite obviously affect the speed/distance a vehicle/travels travels with each tire rotation.  For example, I could upgrade my tires so that I use the same rim, but have a wider diameter tire (taller side walls), in which case, with my current settings the speed would actually start to be a "bit more" accurate as I would be traveling further with each tire rotation.  

For vehicles in the US you can actually purchase vehicle programmers that will calibrate your speedo to a custom tire size (if you didn't adjust your speedo, then if you put on larger tires, you'd think you were doing the speed limit, when in fact you could actually be doing up to 20%+ faster than the speed your guage reflects or smaller tires could mean you would be up to 20%+ slower), else possibly get a ticket for speeding or angry drivers for you driving too slow, dispite your speedo saying you're doing the speed limit.  

Performance programmers from companies like diablosport.com, superchips.com, edgeperformance.com, hypertech.com, bullydog.com a few dozen other vendors all have the ability to change your speedometer calibration based on tire size.  I personally own DiabloSports.com Predator II Programmer (for a 2001 F250 V10), SuperChips FlashPaq programmer (For a 2007 Dodge Ram 5.7 Hemi), Hypertech.com HyperTech III (2002 Chevy Silverado 5.2 V8) programmer, EdgePerformance.com Edge Performance monitor (2007 5.7 V8 Hemi Dodge Ram) on my past four vehicles.  Trying to tune my vehicle to save on gas, yet get better performance as well (more HP).  As well as program for my tire sizes for the speedo as I typically don't stick with stock rims or tires on my vehilcles.

I've got stock tires and rims/wheels now on the Kymco (always have had, and my odometer on the bike only has 1600 miles on it, obviously MORE than reality as the bike thinks I'm traveling faster over a greater distance than reality), so the error I'm getting is not due to any alteration I've done to the scooter.  It seems the manufacturer (Kymco) chose a speedo setting that is made for a larger tire.  OR, it's adjustable and needs to e correctly calibrated.

Hmm...

Well i can see the little wheal you're referring to, you'd swear that there would be some method to just recalibrate the sensor to understand the light pulses correctly as light travels between each spoke as the wheel turns. 

I mean 140Kmh is roughtly 87 mph (that's 17mph difference to the approximate 70mph I'm actually traveling when the bike reads that speed - that's a big difference) and at 50Kmh which is suppost to be 31mph (and I'm only at about 25 mph).

My end resolve is I'm trying to avoid speeding tickets (and obey speed limit laws) from a guage that I have to use as "best guess" to get myself to the correct speed.


The normal translation of kmh to mph should follow this:
Quick KPH to MPH Conversion

KPH  MPH 
30  19 
50  31 
60  37 
80  50 
100  62 
120  75 



Well I guess a test would be then to just put a piece of tape to cover the space between every 7th spoke might change things too.