Well my YZ250 (97).... loss its tranny oil (looks like from the gasket) and i didn't notice.... After riding in the dunes for a while, i shut it down and saw that it had oil everywhere.


after 5mins rest, i tried to start it to head back to camp... and nothing, few kicks then all of a sudden it got "stuck" and wouldn't kick over.


I got my truck and hauled it home....

Now.... the engine is no longer "stuck" it will kickover (i did it by hand)...

but what could the lack of oil have caused?

Tranny toast? clutch? engine?

 

well, I don't know what would happen to a yz250, but I saw a small lawnmower engine today in the shop at school that I think ran without any oil in the crank case and then seized. Well, I can tell you that there was a TON of damage, I think it was the connecting rod that we couldn't find anymore, but there were tiny chunks of metal everywhere. However, this is a MUCH different engine design than a yz250.

I would say that worst case scenario: All you can reuse is the engine block.

Best case scenario: None, or hardly noticeable damage. Refill oil and try to run it at low rpms until you feel safe. (too bad its not a 4 stroke which would actually do a decent job at low RPM)

Either way, Good luck. I hope that you didn't toast it.

 

Hopefully the topend and connecting rod bearing is OK. Unlike a 4-stroke, they are all lubricated by the oil mixed in the fuel and are completely sealed from the crankcase. I can't remember how the 2 outer crank bearings are lubed, but if they are lubed by the crankcase oil, you may have toasted them or some bearings in the transmission. Either way you will have to split the cases. Don't try to crank the engine or it could possibly damage the piston and cylinder if it hasn't already done so.