I have a rmk 800 2000 model, which has covered 5,800km... (3.625 miles).the machine has always been run on full synthetic oil, never over heated as extra coolers are fitted and the engine is standard. I have experienced crank bearing failure. The biggest bearing in the middle of the crank has seized causing serious damage to the engine and alloy casing.Surely this should not happen after only covering 3.635 miles. I was told that it might have been caused by a problem with the oil (lack of oil to the bearings), but if that was the case... wouldn't the bearings at the variator and fly wheel side,with the direct oil feed have gone before the middle bearings ?? has anyone out there experienced anything like this ?
:(

If the other bearings have direct oil feed It should not seize. Is the one that seize had a direct oil feed on it?

I responded to your note on another site but maybe wasn't clear in my reply. I think your problem could be due to rust formation in the bearing while in storage. Was probably getting plenty of oil while running, just no(or not enough) protection while in storage. This used to be a common problem with the early synthetics, but most do a decent enough job now due to new standards(thanks mostly to the outboard motor industry). The fact you are running synthetic oil in no way insures protection against rust, and is a good reason that a lot of people take extra precautions of all types (like fogging) prior to extended storage in order to assure themselves they won't have trouble like yours.

You are exactly right about the fact there should not have been a bearing failure at the milage you are at. Most people would not expect it until it had several times that many miles. The fact the motor isn't known to have a lot of failures is what leads me to believe the failure was due to rust....