I checked 3 bikes on GPS in last few days... result as following.
Honda Pridor on meter speed 83Km/h, and GPS speed 83Km/h too. Amazed at the accurate meter. 
Yamaha Junoon on meter speed 90Km/h, while GPS speed 83Km/h.
Suzuki GS150 on meter speed 110Km/h, while GPS indicated 103Km/h.