The oil pump drive gear (not the gear on the pump itself) seem sloppy to me. Does anyone know how loose this should be on the shaft, or maybe even a spec on the clearance? It looks like (from the microfiche) that the shaft is replaceable, but I am guessing the case has to split (true?) My engine makes a fair amount of noise (more so it seems than other yz's) but the noise has not gotten drastically worse so at this point my guess is that gear is worn. Thanks!