Running 2 stroke engine with slightly worn crank bearing?

[john479]

I got a 1981 TS250ER a couple of weeks ago. I took it for a run and somehow air got into the oil feed to the bottom end and so now the flywheel side has a very small amount of play in it. From a certain RPM up there is a vibration noise. Performance is still fine and there is an oil feed to it now working normally.
I have an enduro coming up and have no time for a rebuild before it, as it needs a rebuild I will by no means be racing, just tootling along and taking it easy. The race is only for 2 hours split into 2 1 hour sessions. Would it be safe to ride it like this? I don't really want to lose my entry money but certainly don't want a major problem caused from running. Thanks very much