This weekend I rode about 135 miles everything was great until I started to get on they main HWY at first my bike seemed to lug down a bit so I down shifted to get up to speed. As I was riding about 70 to 75 it started to act like i had bad gas and cut out, never back fired. Then when I came to a stop it idled a little ruff and started a grinding noise but sounded like plastic not metal to metal. Got home found the left exhaust slip-on loose. Test rode the bike several times since and have not had this problem again. I can't believe that a loose exhaust would cause this problem on a 2000 EFI ultra classic which has no O2 sencors .