Had 13/51 on mine stock and could barely keep up with 45mph traffic while over-revving. Switched to 14/42 and it will now run 65 to 70 steadily on the freeway without any issues and has been up to 95+ on highway twisties. Still wheelies pretty much at will up to 2nd gear and with some planning/momentum in 3rd. You will definitely need a new chain set-up, mine ended up being 110 links (including the masterlink). I wouldn't pre-cut the chain. Set it all up and run the chain loose over the sprockets. Measure TWICE (or even three times) how much length and where to cut it. Take my word, you DON'T want to cut it too short and have to buy another chain or press the links back on. Adjust chain, lubricate, ride your ass off while grinning insanely!
Last edited by 450XSM; 08-02-2011 at 12:04 PM.
09 KTM 690SMC (Gone but not forgotten)
I feel the need for liberation through acceleration.