My 0.02 of wisdom; as in cars, this is a too rich situation, try closing the mix screw totally, and if, engine stalls, this screw is OK; if no stalling, you'll need to get a new carb kit. Somewhere in the forum and other forums there are threads with alternate parts to Ducati OEM's that are a direct replacement.I used to own this 750, which I sold, and eventually bought the Hyper. I was riding this past Sunday and got together with the new owner by coincidence. He says he loves the bike, and he rides it often, but the engine has developed this problem he said;
If he rides the bike hard, it runs good and nothing happens, but if he rides it for a long distance at cruising speed, the engine starts missfiring, and eventually the rear cilynder dies. He stops, changes the spark plug with a new one, and the bike runs "fine" again for a while of one hour or so.
I feeled the inside of the exhaust ( he has a pair of Termis ) and the engine is burning solid black color ( way rich ).
So, I guess he has carburator/jetting problems, any suggestions before we start messing with the carbs. Factory Jet sizes, carb size, Fuel Pump if any ?
Please help, he is just starting a small bussines and has no money to have this done at the shop, so I will help him out, but I ask you for any ideas or imput before I start taking it appart. I will not charge him a penny, so any good will from you guys will just help a fellow Ducatista.
I will post photos of his bike. Anticipated Thanks !!!
Now, if the screw is fully closed and no stalling occurs, then open it by about 1/2 to 3/4 of a turn and have your new friend ride around[you go with him] if nothing happens within the ride, I'd say, problem solved. If not, well, carb redo time.
Hope this helps, mine is EFI so, but, being an autotechinician, this is the way we do it when no gas analyzer available and on a couple or very limited budget race cars of past times.
Enjoy tooling around and riding.