I have my 2009 RMZ250 top end apart now and checked the crank. The crank and rod are pretty stout pieces, but the question of the lower rod bearing is the worry. Up/down and side clearances of the rod all are within spec. Crank main bearings check out tight...no end or side-to-side play. So far all recommendations (from forums) are to change the crank/rod assembly, but obviously that's a fair expense plus the effort of splitting the case, etc. In my defense of being cheap, I still think a lot of advice is still based on 2-stroke engines. A 4-stroke should have better lubrication to the rod bearings if the oil is kept clean. Of course if I don't replace it, I am running the risk of massive engine damage. So......how may of you have had crank/rod/bearing problems, and if so, how many hours were on the engine (roughly)? Hearing from people who have not had a problem for X amount of hours is also welcomed.