When was this engine purchased new? Desert Aircraft has come out with a crank upgrade, which the new DA50R engines all have now. I have been told, that the upgrade is different material or treatment of the crank, resulting in a more wear resistant crank. I have a friend locally, whose DA50R broke the connecting rod while running. Another friend locally had a DA50R that started getting so loose it had become quite noisy. Both engines were covered under the DA warranty. Basically, a tight gas 2-stroke engine will not make as much power as a loose one, so loose is good, to a certain degree. What I would do in your case, is find out where the nearest DA service is, find out if they have a new crank in stock. If they don't, when will they get, or ask the next DA service place. You are really in no big hurry to get the crank replaced, the engine will run a long time still, so try to time the down time to be the shortest and at a time where ou don't need the engine so much.
DKjens