Clogged idle jets won't stop it from revving out. If the mains are still pulling fuel it will still pull. Clogged idle jets will make it idle horribly and bog when transitioning to WOT.
IW
Tat was my point but i guess Lucky doesn't get off the idle jets. 
Actually, it is possible. It would be a very rare thing to have the much larger main jet orifices clogged with debris and the tiny pilot jets
not clogged.
Bike has pods and nearly no back pressure exhaust. This will make the stock carbs deliver far less fuel than it needs, and the pilots do make a contribution at mid range and higher throttle settings. It may well be that pilot jets are part of the problem. Then again klugey bikes tend to have untested and irrational mods made to them; drilled jets, clogged emulsion tubes, carb floats upside down, gas filters clogged with rust and debris, bad points, bad condensers, bad wires, bad plugs, etc. Really, it could be anything, or several things. It is going to take time (possibly a lot) to refine out all the deviations that have been made, and make the bike a working assemblage of parts.
If I were a shop owner, I'd think twice about taking on such a project unless the owner had deep pockets and commited to delve into them. I wouldn't work for free or make donations that would jeopardize my livelihood. Once a shop starts to work on a project bike, they generally own it, as the vast attention it needs, make the bills high and the owner refuses to pay the "outrageous" costs. And, this bike and the very limited number of people interested in it, means it is an all around losing investment in time and money, as they will never get the value of parts and labor put into the bike.
In any case, the spark plug deposits should tell a decent story about how it is running.
Also, taking the head pipe temps, even if only relative to each other, would be useful diagnostic information.
Still, I'd address the normal routine maintenance, if for no other reason than to establish a baseline of known good portions of the machine, thus beginning the process of elimination, and KNOWING what is NOT the problem(s).
Cheers,
P.S. For the record, that bike is NOT a 78 - CB750. Although, it may use an engine unit from one. And, that seems to be the only thing we actually
KNOW about the bike.
Edit: I just took another look at the picture, and it does NOT have carbs from a 78 - CB750. They appear to be an earlier style and painted black, as well.
The bike is going to need some knowledgeable attention, which is best performed by the owner. Unless the owner doesn't mind paying for someone else's knowledge and skill (or their training).
