Maybe wet is not best?
From what I've read a little oil once in a while is OK for the centrifugal clutch, but too much might lead to problems. I found this.....
1) Oil the bushing that is located in the sprocket at least every two (2) hours of driving time. Where do you oil it? Right where you see the snap ring on the sprocket at the end of the clutch. There is a bronze bushing behind the snap ring that needs lubrication. With the engine off, squirt several drops of oil while the bushing is warm. At the same time oil the chain. What oil should I use? A good automotive oil like 10w30 or a straight 30HD weight oil is good, use the same oil used inside the engine. Once the chain gets "kinky" from lack of oil it should be replaced before it does damage to the clutch sprocket. A new chain is cheaper than a new clutch. If you keep the clutch and chain lubricated you should get years out of both. Oiling the chain after it gets dried out is a waste of time. Remember it is preventive maintenance, which means before the items get ruined.
2) Don't put oil inside the clutch. The holes on the drum of the clutch are to let the hot air out of the clutch. DON'T SQUIRT OIL IN THESE HOLES!! When oil gets in the drum portion of the clutch it will cause excessive slippage, which means undue heat will be generated.
3) The oils that can give you problems if they happen to get on your brake disc or in the drum of your clutch are: Slick 50, Dynamite, or Energy Release. These are excellent internal engine oils but will give you "fits" if they get inside the clutch or on the brake disc. They do just what they are intended to do which is to prevent friction -- steel to steel contact. On a clutch you need friction to have it engage and the same goes for a brake system. Because the oil comes out in very minute amounts and gets on the inside of the clutch drum. The clutch would only slip, it would not and could not lock up. This oil will impregnate the steel. Sanding and cleaning with a solvent or gas will not help. Once it is in the metal, it is in there forever because the heat will bring these lubricants back to the surface.
4) If your kart has a grease fitting in the crankshaft for lubrication then a shot of grease twice a month should be sufficient lubrication. The grease is coming from the inside of the sprocket outward, which is a better way to lubricate the clutch. The keyway in the crankshaft acts as a reservoir for the grease, which cuts down on the frequency needed for maintenance compared to oiling the snap ring area. The chain still needs to be oiled frequently to keep it from kinking up. There are some excellent chain sprays available that are waxy and will not let sand and dirt adhere to them. Dirt and sand will wear the chain as well as the sprockets.
If your go kart takes off by itself when the engine is started, with no one in the drivers seat, that is an indication that the clutch is badly in need of lubrication. Turn the engine off and park the machine up against a tree or fence to prevent it from taking off when you crank the engine again. You can also put the rear end up on centerblocks so the rear wheels are not touching the ground. Lubricate as needed. Give the lube enough time to penetrate, then start the engine. If the machine continues to take off by itself even after the clutch has been oiled, the clutch is burned up and must be replaced.
How long will the clutch last? If put on the crankshaft properly and observing all the hints that are pointed out in this article, a clutch should last many years. But if it is improperly installed, driven in abusive conditions (lack of oil, sand, steep terrain, excessive weight in the kart, wheels that are to tall), the clutch might only last 20 minutes.
