I just purchased a 2002 RC51, and am wondering which model it is, SP1, or SP2. And how do you know the difference?

SP2.

2002-2006 are all SP2

I just purchased a 2002 RC51, and am wondering which model it is, SP1, or SP2. And how do you know the difference?

The '02 is difficult to tell apart from the '00-'01 models.

If stock, the swingarm, wheels, and upper cowl brace are the easiest way.
The SP2 swingarm is a different design, the SP2 wheels are 5-spoke vs. 6-spoke, and the SP2 upper cowl brace is aluminum vs. steel.

Of course the '03 and up are easy to distinguish.
However, they're all good.

Gotcha, thanks for the responses.

The '02 is difficult to tell apart from the '00-'01 models.

If stock, the swingarm, wheels, and upper cowl brace are the easiest way.
The SP2 swingarm is a different design, the SP2 wheels are 5-spoke vs. 6-spoke, and the SP2 upper cowl brace is aluminum vs. steel.

Of course the '03 and up are easy to distinguish.
However, they're all good.

What do you mean? The 02 and 03 are identical.

well you are close they are close but different first of all the things that sub said plus the tail section plactics are different; 20 has a silver tail with a black oval on each side and the 03 has a black tail with silver ovals. I also beilive that the side fairings might be slightly different but not entire sure about that

Exactly.
The SP2's are mechanically the same.
The SP2's differ mainly in cosmetics.
The lower cowl graphics differ slightly in the size of the hawk feathers as also the feather tips that are on the tank.
The size of the RC51 font is also very slightly different as well.

Graphics may differ, but that I do not consider. You can buy a black or a red SP2, it will still be a SP2.

You wrote that 00-01 are hard to tell apart and 03- is not, and I beg to differ. SP2 arrived 02 and is different from 00-01 in many ways, some what you have mentioned.

you are correct the 02 is different form the 00 and 01 however the paint scheme is the same as the 00 and 01 so there for is is hard to tell them apart that is all he was saying. if you lined the three years up side by side you would be hard pressed to tell the differences from a distance or while they were moving. however upon closer inspection you would be able to tell the 02 aprat from the other two that is all he was trying to say.

Obviously we don't have the same paint schemes in Europe as you have in the states.That I understand now :)

The -02 here is white, as mine, while the -00 was red/black and -01 was either red/black or silver.

I didn't mean to be rude, just to clarify from missunderstandings. I see more with repainted fairings than updated swingarm/rims.

Yes indeed the Euro cosmetics were decidedly different than the States.
Our only model that had a bare metal frame was the '04 while most if not all of the Euro models had bare frames. Except for the '05-'06 which may have had black frames.
Correct me in that regard as I was unaware they offered the black color in Europe until recently.
I still admire the SP1 red/black graphics with the gold wing on the tank. Very classy.