You are right, different size tires should affect the speedo. I have a GPS mounted on my bike, so I can compare the speed on it vs. the speedo. Since I went from 25 to 26 I don't think there is much difference, but I will check it on the weekend if I remember.

 

One other thing about larger tires. If you get wider tires in the front, I got 26x10x12, make sure you get the fender flare extension kit. If you don't you better like wearing the mud/water you drive through.

 

The Honda has a different bolt pattern, otherwise I would have done a test swap.