Okay, this isn’t really a spoiler, but I felt like giving some GTA IV advice.
Ever notice you hardly ever see any great cars or bikes driving around when you need one? Well…it’s sort of a Catch-22. To get really good cars to pop up, you need to be driving an expensive/nice car. Same with bikes. If you want to rip off a bike, it’s easiest to find one…when you’re riding a bike.
So my advice to you — and what I do — is when you get your hands on a really nice car, park that sucker in reserved parking at one of your safehouses. Same with a bike. If you want to go out hunting for a nice car, hop in your nice car and look…right near your safehouse. If you’re lucky, you’ll be able to make it back with both cars (provided you have parking space available for them).
Same with a bike. You want to rip off another bike, keep one stashed somewhere. Get on it, and I guarantee you, you’ll start seeing more bikes than usual.
Hope this helps a little. 😉