just bought an 06 F4i, mostly stock except an Akropevic slip-on and an upgraded "front sprocket." I'm new to bikes, but the dealer told me that the owner put on an upgraded sprocket that increases the low end. Being that I'm new, i really don't need the extra concern of that lower end power until i am more experienced.

My question would be, what exactly was done to the bike with that upgrade, how much does it change the power characteristics, and would it be logical to go back to stock, or keep it as is?

 

if the front sprocket was changed, it was most likely a tooth down from stock, which makes it accel faster. There should be a part or box under your seat that is aftermarket and wired in to the wires near the batt box. This is a speedometer fixer because when you change the gearing in the front sprocket, the speedo and odometer gets thrown off. You need to look for the aftermarket part, count the teeth on the front sprocket and to be careful the rear as well. There should be 16 in the front and 46 in the rear. If you dont find something that corrects the speedo or you drove next to someone and your speeds were really off, you need to get one or change the gearing back to stock. it will throw off you milage and your speedo.