In my ST12, the bearings were installed without cleaning out the cosmoline like substance. Running my genhead just made that stuff dry out all the more. By the time I took mine apart, it looked like semi dried varnish and smelled bad.
I took the genhead apart and lubed them up with some standard EP-2 grease. these bearings are on mine are not sealed type, and there is no provision for a zirk fitting.
Eventually I'll have to open it up to re-lube the bearings, or put in some form of fitting so I can squirt some grease in there, or get some quality sheilded bearings...
But for sure, you will have to do something right away.
Scott E