I bought a zx7r once as is always wanted one, the one in question was 4hrs away in Portsmouth on the army barracks ( forget which one). Luckily my sister lives in Fareham so I made a weekend of it so if the bike wast any good then all was not lost.
Got to the barracks, test rode the bike, sounded well and was clean for the price so I bought it. In my naivety I should of taken the bike off the barracks as there was a speed limit which I had to stick to and when I got back to Manchester I found that it wouldn't go over 100mph!!!
I ran the guy I bought it off for his missus to say he'd been deployed (how convenient). It cost me a further £360 for a dyno jet kit as he had been messing with the needles that much that he knackered the while set up!
Just a word of caution from someone who's been bitten doing the same thing. Hope your sale goes better than mine did chunko