| stock is stock. after market rear sprockets do have certain prints which is easily identified eg 60 , 70 ect. its not hard to count is it ? also when say a stock cag is fitted with gearing to get to the 100 k mark you must remember that this will take some straight track but revs will still be simular, its the gear down process. lets say your engine is running at 10,000 rpms with a 6 - 68 ratio and you only get 60 kmph top speed, if you go to say a 9-60 ratio and when your engine reaches 10,000 rpms i would say you are going alot faster than 60 ks. | 
