Anybody ever think maybe the current practice of using a large diameter prop and loading the engine down might be part of the problem ? Like running up a big hill in your car in high gear--it WILL do it, but why ? The auto transmission shifts down to keep the engine in the power band..Running a 24-8 on a 50cc engine is kinda the same..That little pressed in roller bearing on the big end of the rod is working very hard...I haven't seen a mention of where the max torque is on a DA 50, so maybe I'm all wet...OR the bearing is too small..OR the aluminum rod doesn't hold the thin shell of the bearing tight enough, hence the new steel rod...
If they would use a case hardened steel rod with a chain saw type roller bearing running on a crank pin with a hard enough surface there would be no problem..But that would cost more...And there would be the problem of the bearing sliding out of the rod..OPS did this with their 30..They used a washer held on the end of the crank pin with a left hand thread screw..How do I know ? Tried to unscrew one..
Maybe DA should ask Brison how they did it--theirs works....