I would ask him 'do you feel the bike is in "Good," "Very Good," or "Excellent" condition?'
An honest seller won't b.s. you about the condition. If you're dealing with an honest seller, I personally think it is okay to be a shrewd buyer. So after asking the question above, if the seller says 'the bike's in Excellent condition' but it's clear the bike is only 'Good' or 'Very Good' -- the seller is dreaming and I spend about 2-5 minutes trying to get the guy thinking logically and if he won't budge I walk.
Paying an "Excellent" condition price for a "Good" or "Very Good" bike is not cool because you can go out there and pay the same price for an authentic "Excellent" condition bike. If the seller wants an "Excellent" price for a less than excellent example I walk.
If he's honest about the condition (low miles doesn't mean "Excellent", what about tires, paint, rust, brakes, overall cosmetics, seat condition, does it smoke, is it all stock, etc.) if he's honest about the condition I either show him the most recent "Completed" ebay sales for that bike and/or show him the Nada pricing.
I think $2000 is okay if that was a garage queen but it was "found it in a barn in Seattle".
At best it is 'Very Good.'
Here's the Nada numbers, I live in Silicon Valley, if that bike went on Craigslist in San Fran or San Jose it would take quite a while to sell at $2000 if at all, and theres lots of high tech money here of course putting upward pressure on prices:
1978 Honda CB750F SUPER SPORT
Pricing
Excellent $2000
Very Good $1275
Good $725
Fair $550
Poor N/A
http://www.nadaguides.com/Motorcycles/1978/Honda/CB750F-SUPER-SPORT/ValuesIts a BIG drop from 'Excellent' and if the bike was 'in a barn' and then a 'daily driver for 2 seasons' it won't be 'Excellent' most likely.
I suspect vintage bikes here in Silicon Valley sell for at least as much as a few miles up the coast there where you folks are. Good luck man, everything's negotiable, go for it!!!!! The 750f is a cool machine.