i had the same sled. i never touched the main jets , but i did drop the needles 1 notch. the sled really woke up after that. ran it like that for 11000 miles. plugs were always perfect. engine was stock with air tubes removed and a clutch kit. best sled i ever owned.
I have a 2003 xc 600. I dropped the needles one and It runs good. Just have to keep the exhaust vales clean its pretty easy to do every 800 miles or so.I played the game with running them lean.all done with that I would rather ride then put engines together.