allright, if your not already confused with the 520 conversion, my suggestion is don't bother changing your gearing, it really depends on how you ride, going up two in the rear or one down in the front simply gets you better acceleration, yet you lose out on the top end, your choice, also it makes your bike run higher rpm's, not good for long distance or highway travelling, also, your speedometer is not accurate when you change your gearing, therefore, your adding additional miles you never put on the bike, besides, you never really know how fast your going... I did this mod and yes it was cool...for awhile, I am now back to stock as far as gearing goes, but maintained the 520.
Szokr1