No, but i would change the rear sprocket and leave the front alone, problem is with changin the front if you go smaller is it will wear out your chain much quicker, which isnt a huge difference but every bit counts.
Originally posted by Jammin_Johnny Gearing will change and effect the "acceleration" & "velocity" rates of the machine.
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Jammin_Johnny's right and it also depends on how many gears you want to run through. On my 1K with stock gearing I would go through 4 gears running low-mid 10's at 130-135MPH sea level. I didn't change my gearing however I did buy that 44 tooth rear but I didn't play with it to see if I would have to shift into 5th. Which would have probably slowed me down and since I couldn't get the 1k into the 9's (yeah I know I suck) why would I want to go slower.