if i have been reading threads on here correctly the f1 has the same engine as the k7 or the k7 has the same as the f1... and think you have covered the main points, there are certainly enough people out there with the f1 to ensure all the parts you need are still avalible. and when parts are for a K, doesn't always mean they won't fit the F.
And with your vision as is there will be numerous custom parts, so you won't be worried about standard parts.
The big plus is obviously the rear disc brake, much easier than the drum, i have a k7 which will prob end up with a rear disc anyway.
as gregimotis says i would ask the question as to why the carbs are off and selling, a rough running bike is still better than a non runner...Carbs being what they are (as i am trying to sort mine at the mo) there are plenty of people out there who will help you with them,
i would get a compression test done and check the spark before handing over $900, as if they are ok then thats the major elements check other than the carbs..if all ok bump him down a bit because of the carbs and jump in..oh and 19000miles is nothing for one of these bikes so unless it has been total ignored should be basically ok.
I have only been part of the SOHC crowd for a wee while and advice on here is always tip top along with any manuls and you should have all the help you need.
