ok so i got the 43 tooth rear sprocket not sure if the fron is the 15 or not but my speedo is 10 mph highr than what im actually doing.......50mph on the speedo = 40 mph anyone know what would do this?

 

Change of sprocket sizes...

 

If you changed sprocket, your speedo will be off.......the more drastic the change in size, the more drastic it'll be off. The only way to fix it is to get yourself a "speed-o-healer" unit to re-calibrate it.

 

i just got the bike i didnt change anything and the rear sprocket is a 43 tooth like it should be. so what next?

 

Even stock is off, the only way to truely know (99.9% G.P.S. Accurate), is throw a healer on her!

http://www.healtech-electronics.com/

 

ahhhh i just took a look at the front sprocket and it's a 14 tooth.[:@] WTF! granted its great if im drag racing or stunting but that's not what im doing lol so now i gotta find a 15 tooth. will any year 15t cbr front sprocket work?

 

10mph off at 40mph... and probably 30mph off at 120mph.

even with stock sprockets you'll have speedo error. i have stock on mine and i'm 10% off (10mph indicated = 9mph, 100mph indicated = 90mph)

everything has speedo error. even your car.

 

you want a 16 tooth

 

y a 16 tooth?

 

As Fly stated even with the 16 tooth your going to be off, bikes are 5-10 % off right from the factory, usually about 8%.