short list
1979 Honda CR125
2007 Suzuki GS500F
2008 Kawasaki Ninja 650R (Sold)
2011 Yamaha FZ8
I think my favorite was my old dirt bike. I rebuilt the transmission, dissasembled and cleaned the whole engine and learned a lot along the way!! ( the kickstarter gear sheared off and went through the transmission, it was not pretty) This is also where I learned to check the oil pan for metal shavings when buying a bike!