All Honda speedo's are about 7% optimistic at highway speeds & this error is not linear. At 140mph it may be off as much as 14% or more & if you change your sprockets to a lower gearing the error is even greater!
I use Jim Ahlmans recalibrator on my RC51. I did the testing on both his gen1 & gen2 prototypes & never had a problem plus his units are plug & play no cutting or splicing of wires.
How much does it cost? i dont want to spend a crazy amount of money on something ill just use once, or do i have to use it multiple times? if anybody in ohio wants to let me borrow theirs the post and ill ride out sometime. im always lookin for a trip somewhere.
Travis I have the speedohealer for my 929 I bought from Calsportbike for 85 bucks. It is well worth the money as it is a plug and play also so no splicing. It is very easy to install and set. The results you will get are a true speed and odometer reading.
mine 7mph off most of the time, and i just learned what speeds i need to go at certain speeds i.e. in a 45 zone i usually go 60 on my speedo, that would take me to 53 and thats 8 over no cop is really going to pull you over for going 8 over, and etc