I posted this in the supermoto forum also...last month, I put my 03 YZ450f on the street. I haven't done the conversion yet....No lights,no nothing. I plan on building it this winter, nice and easy so that it's ready come spring. I still want to do moto with it, so I'm keeping all of the dirt stuff. So here goes. I would like to know what the general ruling is on rear sprocket size. I wanna keep the front sprocket right where it's at to ease the weekly swap as easy as possible. I will take it out on the hi way on occasion, and I don't want to rev it, but want to be able to get going without killing the clutch. I had an '00 XR650R that had 14/43 and it cruised at 75mph nicely. Thats what I'm looking for. Thanks, Kelly from Crapchester NY.