I've been test riding a few bikes recently, one of them which I really liked the look was a 1997 Yamaha SRV250 which I basically had my heart set on until I took it for a spin. The problem was that when I got off, the thing I felt like I was sitting on a jack-hammer instead of a bike. The thing was vibrating so much that even at 60km/h in 4th I could barely read the speedo. I was very disapointed because its a beautiful bike to look at with a lot of character. Just the absolute pits to ride... since then I've got my eye on a Zeal which is SMOOTH as. Anyway... What makes a bike vibrate like that, and is there something seriously wrong with it or just how some bikes are?