Rev limiter: a little old but good topic, I was wondering myself.  Here is my input for what its worth. My 2005 Suzuki Savage LS40 650 Thumper has 6,500 miles then converted to a RYCA  (not a purest) cafe racer. Elevation Sea level. Carb. jet needle: removed white spacerand installed three washers provided by RYCA. main jet 155. pilot jet 55. pilot screw 1.5 turns out.  Air filter  k&n. Muffler Harley Dyna. New Elec. Tach. Speedo. Direct drive.  Fifth gear 60 mph turning 4 thousand rpm.  She sounds great so I cut her loose . First gear 7,500 rpm no stamer. Second gear 7,500 no stamer. She was still climbing and I backed out!. So, I would say if there is a rev. limiter it's way up there. Hope this helps out. Have fun! Phantom