I check my oil level regularly, and tighten the oil plug finger tight (as tight as I can get it with my fingers). Apparently, on my bike at least, finger tight is not tight enough. Twice now, after rides of 40-80 miles, I noticed oil leaking. The first time the plug was loose, but still screwed down. The second time the plug had completely come unscrewed. Now I'm tightening the plug with a pair of channel locks. Not too tight, because it is plastic. Anyone else had this problem?