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Does anybody know the output shaft rpm? Every single bike I have ever owned, I have went with a -1 front sprocket to get faster acceleration at the expense of top speed. However, with the 125, I notice slower acceleration and top speed. I have done extensive testing and noticed that the stock front sprocket (14t) has better acceleration (and obviously) top speed than a 13t. Maybe if I can figure out the output shaft rpm, I can do the math and figure out why this is? At some point I know you can get too small but I didn't think it would be 1 down from stock.
 

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Not sure but using gearing commander does seem to show slower acceleration with 13 Gearing Commander ⚙
 

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Horsepower on this bike trails off at 8000 RPM. With a 13 tooth sprocket and no other mods, you are dropping to about 7800 RPM when you shift at 3rd gear redline into 4th. That could be a big part of your problem. Gearing can be pretty tricky to get perfect. Some bikes see acceleration gains by going to taller gearing. On higher powered bikes, taller gearing can smooth out wheel slip a little as well helping with acceleration.

I've heard a lot of people say that for performance, stock gearing on this bike is just about right. Stunting is a bit different, of course.
 

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I don't have a way to test but I'm thinking in order to take advantage of 13T you will have to shortshift 1st gear. Because first is barely there as it is, so making the gearing ratio higher will make it very short lived. So by revving it out normally you're going to lose a ton of acceleration.
 
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