Typically wrong speedo is change to tyre rolling dia. Anyway even from factory, speedos are often a fair bit off. The Honda speedo gear is driven bt the differential where it turns at wheel speed so the FD does not influence it. I can't speak for different models
my cable speedo is increasingly off. its a little ahead till 20. on till 40 then at 55 its showing 60 at "90" im only going like 78-79. So much fun for a passenger though. "OMG we're going 120 slow down!"