Might want to buy a new chunk of chain, if the chain starts to wear it will eat your sprockets then your back to looking for a sprocket with a splined hub. Also invest in some quality chain lube, we like some stuff from Multi-Mist called X-433. It has a mixing ball in it just like a can of spray paint, has graphite and molybdenum in it. Another good bet is any quality name brand chain lube for motorcycle chains like Bell or Lucas. A local agricultural dealer will offer some good chain lube as well, we usually use stuff from AGCO or New Holland and some guys swear by the stuff from John Deere. No matter which stuff you buy run it a bit first to get the chain warm then spray it, a warm chain will pull any lube into the pins and bushings where the most wear occurs. I like to lube em when I'm done with something so it has fresh lube in the chain to prevent any rust from forming.