Speedo accuracy?

[Morcs]

Has anyone tested how accurate the stock speedo is with GPS?

Ive got a speedohealer on the way, and wondering what % to factor in for factory speedo overread.

Many thanks

EDIT. used search function...

 

[Nobby]

I checked mine against gps & found it to read 6% high,that is 3kmh at 50kmh & 6kmh at 100kmh.So at an indicated 100kmh I was only doing 94kmh

ps:my bike has stock gearing

 

[Morcs]

Yeah I was thinking of factoring in 5% for factory error.

Cheers.