Hey,
"They" make a 1800 rpm 60 hrtz 110V generator head which employs 4 coils instead of 2. Who? I don't know do a Google search for them. I've considered such for my Kubota 300. My small diesel likes to run at 1800-2000 rpm, so I MUST gear up to get 60hrtz from mornal 3600 rpm genheads. If I had one of these 4 pole machines I could more closely match engine best rpm to genhead output cycles. Form what I've seen they're not cheap, but there's always that option, for me.
Now, what make of engine is powering the genset? Does the current genhead have a coupler from the engine crank to the genhead shaft, or is the engine itself serving as the genhead inside bearing? If it is a coupled type you can easily modify the gearing, if it's the other type don't mess with it too much. The later also has an engine oil seal to worry about between the block and long crankshaft bolted to the genhead rotor. If engine or genhead fail, in the later, the entire machine must come apart. In the former a failure means removing one or the other, maybe.
Unless and until I make my own biodiesel, like Pepa is, I really don't like running the Kubota at all. I'm extremely pleased with my solar array. If I could only match or exceed the 750W PV with a wind machine (or 2)......
Good luck,