[beatr911]

Increasing the sprocket tooth count and therefore diameter of the front or drive sprocket makes the wheel spin faster in relation to engine speed. Decreasing the sprocket tooth count of the rear or driven sprocket makes the wheel spin faster in relation to engine speed. And vice versa. Its all about leverage.

On my 200 I went from a 15 front and 46 rear to a 15 front and 40 rear. It's really tall for this little engine. Engine speed at 60 mph dropped from a calculated 6950 rpm to 6000. Search for 'sprocket calculator' and get your manual out to plug in values for your particular bike to estimate changes you would like to make.

One thing to consider is that when gearing 'up' or 'taller' like this, first gear isn't affected as much as the top gear. The change is evenly spread out through all gears, spacing the rpm change between each gear out a little more. Most people that ride on the street like the taller and wider spaced gearing over the typical close ratio, short gearing that comes stock. On a racetrack or when you are accellerating at maximum repeatedly, the close ratio gears are useful for keeping the engine near maximum output rpms through successive gear changes. Most street riding doesn't require this.