| The other alternative is to buy a proper race bike-GP250 class like my TZ, mind you at 6ft 3in you may find them a bit of a tight fit. I use mine for track days and it will easily keep up with a CBR600 or R6 on the straights and then absolutely murder them round the corners. 80bhp and 103kg on slicks will do that for you. There is a guy who has made a 350 conversion for the TZ 'V'twin which I am considering, that will allow it to run in the open class with 95 bhp. On a tight twisty track like Cadwell it should be ok amongst the R1's and the like.
Whatever you decide just enjoy it. I got the TZ 'cause it only cost me £2000 which I can afford to throw away if I wreck it. A simple lowside will cost me more than that on the duke.
John | 
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