From Boca Bearings web site. Looks like a good oil is fine for a onroad kart
SEAL REMOVAL, CLEANING & RELUBING
If your bearings start to feel gritty or noisy it is most likely a result of dirt or debris getting under the seal or shield. Your bearing’s life can be extended with a simple cleaning and relubing process. If you are not comfortable doing the maintenance yourself you can send your bearings to Boca Bearings and we will do it for you free of charge.
Removable metal shields have a c-clip that hold the shield in place. The c-clip can be removed by running a pin around the inside of the outer race, once the clip is removed the shield with pop right out. To remove seals from the bearings, you can just gently put a pin or awl under the inside lip of the inner race and pry the seal off of the bearing. Soak your bearings overnight in our Clean Touch bearing cleaner or any standard degreaser, then blow the bearings dry with compressed air or allow them to air dry over night. Depending on your desired goal you may want to relube with either our High Speed Oil or Grease Power. Typically you will want to use grease for off-road or dirty riding environments and a light oil for on-road or clean riding environments.