i would not waste the money and effort to do it. i did a little test today with my hand held gps. speedo indicated top speed of 103 on the way to work and held at 100 for a half mile or so be sure sure it took. got to work looked at gps, 99.3 was the max speed on the gps. not enough error for me to drop the ca$h and time to install a healer. plus it is just one more electronic thing toact up.

 

Then you didn't change your gearing or your method was incorrect (I am NOT trying to be rude)

If I remember correctly, it was about 10% off after going -1 (ie. 7 mph off at 70 mph).
I am going by memory right now, but I did verify mine with a GPS at the time and it was connected to no less than 5 satellites.

 

no offense taken, i am always looking to learn.

i definatly changed the gears,i am down one in the front and still stock 42 in the rear. yes i did buy the bike new so i am the only one who has touched it.

as far a method.
all i can tell you is i turned on my Garmin eTrex beforei left the house made sure it had picked up signal before i shoved it into my pocket and left for work.no idea how many satellitesit looks for, if i remember correct it shows 4 on the screen. i get onto the eway at one point and was able to have enough space to wind it up a bit, held at speed to try and be sure it picked up correctly. when i got here i looked at the max speed. not really sure how else to change that method. i have been trying to see where i could attach it to the bike so i did not have to put in my pocket or try and hold it in my hand.

when i did the change the geari did anticipate error. i figured it would be what i changed the ratio by 6.25%. so at 100 i should be off by about 6mph


all things have some kind of error. i am sure my speedo is not 100% accurate, and i know the gps has error. i have seen it indicate that it is only accurate up 50 feet or so at times based on the signal it is receiving. i will try a follow up run to verify my results

 

o.k. did test #2 today. with gps in hand and watching as i carefully road along. ( two laners this time not the eway. ) early sunday is a good time due to less cagers.

anyway, noted 61 on my speedo, and 56 on the gps. more in line with onarom. but still have no idea of how accuracte the gps is. did a test against my buddies stock gixer. he was showing 3 to 4 mph higher than the gps with an indicated 50 on his speedo. i was showing 53 to his 50.

just a little more info for you all.