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Discussion Starter · #1 ·
I was just wondering if anyone knew wheather or not by changing the front sprocket on my 2001 ZX-9R if it will make the mileage count up faster because it throws the speedometer off. If it does then i will have to get the yellow box to correct this problem. I dont want my bike racking up miles then ive been covering.
 

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I would say just test it. Get on the highway and start counting at a mile marker. Go about 10 miles and see if there is a difference. I heard that even with the speedo being off the odometer is usually accurate. I have a 9R with the changed sprocket. Ill test mine out this weekend and let you know.

 

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The speedo/odo pickup is either on the front sprocket or the front wheel, depending on the bike. The ZX-9R has it on the front sprocket.

And, having dropped one tooth on the front, it changed the speedo a little, and the odo a little less. The speedo reads about 5-10% high, and the odo is only 3-5% high. (compared to my GPS readings)

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Why would it change the speedometer and the odometer to different degrees? If you change the speed of the pickup by say 10%, they should both change by 10%. Does that make sense to everybody else?

 

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the speedo and the odometer (without knowing the algorithm they use to calculate either) should/would change the same percentage. Quick math works like this:

Stock 9R Sprocket is probably a 15T
Replace with a 14T (-1)
% Difference: 6%-7% (Depending on how you score at home).

Since both the speedo and the odometer are based of the same rotational speed indicator (sensor found mounted in your sprocket housing, with a magnetic pickup on either the sprocket or the nut that holds on the sprocket), they should change the same. A lot of people (including myself) use a Yellow Box from Black Robotics to recalibrate their speedo/odo and eliminate the error.
 

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Discussion Starter · #7 ·
Well standard ZX-9R is a 16T. The mechanic a Kawasaki told me the speedo picks up off the washer that holds the sprocket on. I also did some comparisons with other friends on bikes and found that my speedo was only off about 2-3mph. I can live with that. All I really need to find now is a radar box on the side of the road that tells you how fast your going.
 

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Fat6R, you are correct that both instruments will change the same, but you have to deal with the fact that the speedo is deliberately miscalibrated to read high at the factory while the odo is exact. This is true for most sportbikes, usually in the 5% - 10% range.

 
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