I am looking at building my 400HO up,adding bigger tires.

How can I recalibrate the speedo/odo for larger tires? We road ride legal up here, so it is important.

 

You can't unless some way to alter the wheel speed sensor to compensate.Most guys that did this at the shop and then compared them side by side to stock machines only noticed a couple mph difference between the two.25/10-R12 vs 27/11-R12 Tire Comparison - Tire Size Calculator

 

Thank you OPT. Won't worry about it then.

 

If you're going from 25" to 26" add 4% to the speedo and odometer. If you're going from 25" to 27" add 8%. On any other sizes just divide the bigger tire diameter by the smaller tire diameter and it gives you the percentage difference. It will still be close to 4% for each inch.