Might have been me, with the G9 style clutch or the newer roller clutch that huge cover seems to keep the dirt out. I sprayed it all down with brake clean then used superlube spray on the pins and links that move...and not a lot just enough. Grease the zerk for the center bushing and it was all set. Make sure no grease/etc comes out anywhere before you put the belt on, can't let it get on the belt. Some old carts like G1 might not have zerks on primary (the original clutch) or secondary iirc some G2 do not have. Zerk is near the ramps on the secondary on back side, otherwise I use a little lithium spray grease through the spring, carb/brake clean to clean it.
A good chain lube for motorcycles would work. I just like the superlube because it is synthetic so it collects less dirt. Its clear, it goes on runny then dries to a light grease film that stays around. I bought it local. It is good for a lot of different things like door hinges because it makes less mess and you don't see it. Its not a real heavy duty lube, the grease version in the tube might work better for a 'grease' application. It looks like vaseline.
I used a lot of superlube for chains, it does indeed collect less dirt. The spray version comes out kind of runny so it seeps into the chain, but then it dries into a light grease, that initial penetrating action it is ideal for chains.