You can find centrifical clutches with bores as large as 1-7/16" for industrial engines like those used on reefer body truck compressors,but be prepared to drop a big wad of cash for one!..unless your lucky enough to find one at a scrapyard or something..
I liked the go-cart I had with a belt driven jackshaft that had a chain driving the rear wheel...with that setup I could "pop the clutch" and do awesome burnouts and dounuts,get faster take offs,etc,than the "slip & slide" centrifical clutch..I set mine up with two different sized pulleys ,so you could move the belt to the other ones for a lower gear ratio,for when I drove the cart off road,for better hill climbing..a 5/8" belt works best and lasts longer than a 1/2" one..