I think most of this has been covered in the various other threads on this topic but, here we go:
What will each type of change do?
If you drop teeth on the front sprocket, or go up teeth on the rear sprocket, then it will give you greater acceleration.
If you go up teeth on the front sprocket, or down teeth on the rear sprocket, then it will give you a higher top speed, at the expense of worse acceleration
A change of one tooth at the front is roughly equivalent to going almost three teeth, in the opposite direction, on the back. e.g. -1 at the front is almost equivalent to +3 on the rear.
If you go -1 at the front and -3 on the rear then its really a waste of time and the change will, to a certain extent, cancel each other out.
Here is a useful website where you can input your bike and it will show you the effects of just about any gearing change you can dream up.
Does it give me more horespower?
Changing your gearing doesn't give you any more hp, it just plays about with the rpm you'll be running at certain speeds, in certain gears (you can move the power to where you need it).
Type of Sprockets:
Front sprockets will always be steel. Usually, you will have three main choices of rear sprocket material:
- Hybrid (steel teeth/aluminium centre)
Steel sprockets should be more durable, at the expense of being a little heavier with less efficient power delivery to the rear wheel (more mass for the engine to turn).
Aluminum sprockets are said to be less durable but are much lighter than steel, allowing more efficient power delivery to the rear wheel (less mass for the engine to turn).
Hybrid sprockets attempt to offer the middle ground between the two; providing good durability and a reduction in mass over an all steel rear sprocket.
If you are changing your gearing then it makes sense to change your chain at the same time. Using an old chain on new sprockets can increase wear. In any event, your old chain may not be long enough for the new sprockets anyway.
If you change your gearing then it will mess up the calibration of your speedo and, therefore, your odometer.
This can be fixed by purchasing and programming a corrective device like a Speedohealer, or SpeedoDRD.
You can work out the exact calibration value using a radar gun, dyno or, if you are of a masochistic ilk, speed cameras/police officers!
There are also tools on the following websites where you input the details of your bike and the gearing changes and it will give you a calibration value to input into your chosen correction device.
Another side effect of gearing changes is that, by chasing acceleration, your fuel consumption may suffer (You will be higher in the rev range more often).
Most common changes for a CBR600RR:
The most common change of gearing for the CBR600RR has to be going down one tooth at the front sprocket and up two teeth at the rear (-1/+2). This gives a noticeable increase in acceleration whilst still maintaining a reasonable top speed.
Many users will also convert to a 520 pitch chain and sprocket set ("520 conversion"). The bike comes stock with a 525 pitch chain and sprocket set. You can only use a 520 pitch chain with 520 pitch sprockets and you can only use a 525 pitch chain with 525 pitch sprockets.
The main reason for going to 520 pitch is that the chain, in particular, will be smaller and lighter. This reduces the rotational mass in the drivetrain. The theory is that this will allow a greater transmission of engine power to the rear wheel, as less energy is sapped in turning the chain and sprockets themselves.
Some fear that a 520 pitch chain is too small and weak to handle a 600cc sportsbike. The quoted strength of the higher quality 520 pitch chains is, however, more than enough to actually handle most 1000c bikes, let alone 600s.