My wife just got an 08 650 custom. Ive been trying to learn about them. We did a J slam on it and lowered it four inches in the rear and put some phats risers on it to bring the bars back two inches wife is vertically challanged at 4'9" she can flat foot it now. Ive been reading on all the forums and ive not ran across anyone who has been able to change the gearing on them. I ride a Suzuki c50 and a guy in ohio came up with a way to swap out the gears from a c90. It reduces the gearing by 14% so now when I ride at 60 mph it revs like it use to at 52 mph. I really love it. You wont hurt that 650 running at highway speeds these motors are short stroke and can easily handle the higher rpms. anyhow keep surching maybe you will find an answer but ive never heard of any options. this pic was taken before the risers were put on. Thats my c50 in the back ground.
