Worst bike you ever bought and why

[LongRanger_imp]

Yep, the '06's and '07's were notorious for piston slap. I owned two '07's and had no such issues but it sounds like yours was a dud. BMW issued a worldwide recall to inspect and replace the rear wheel bearings, so no big deal there. Many ST owners do complain of stalling, which is easily rectified with new fuel and vent lines, but not under recall or warranty. Sometimes the IAV is an issue too.