so i went and counted mine, i have 46. What does this mean? how can i tell what chain it is? My speedo is waayyy off

 

It means whoever had it before you changed the rear sprocket. Unless he installed a speedohealer or other speedometer correcting device, your speedometer is off about 7% (reading too high). Check your front gear, you may have a 15T up front as well. If you have a 15T front with the 46 rear, then your speedometer would be off about 14%.

As far as the chain is concerned, a 520 is thinner and lighter than the stock 530. If you compare it to a stock bike and yours is thinner, then its most likely a 520.

 

SprocketSpecialists.com offers a split rear sprocket that doesn't require removing the rear wheel, but you gotta remove it anyway in your case to get the old one off! So it's your call - and SprocketSpecialists ain't the cheapest around.