my bikes were, honda XL125R. honda CB125. Suzuki GSX250. then straight on to a honda CBR1000FH. got plenty of experience(usually by falling off) on smaller bikes then moved onto a better ie more expensive bike. oh hang on?? i still fall off!!
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if you buy a smaller duke (600ss/600monster)they are easy enough to handle to gain experience. cheap to buy. and when you are ready to move up you should'nt lose too much money.
low insurance group.
good looking/sounding.
and its a Ducati.
Best of luck.
Gordy.