Motorcycle Repair: Yamaha BW200, yamaha bw200, yamaha bw

Question
Falcon,
As you can tell from the subject line I have a 1988 Yamaha BW 200.  I bought it knowing I'd have to rebuild the top end. I installed a new piston, rings, and cylinder. I finished that according to the Yamaha manual.  (All that so you'd know it's mechanical condition) I was riding in Montana in 30-40 degree weather last week. While in the garage, I let it warm up for about 5 minutes. I checked the oil and didn't see any in the sight glass. I put a pint more in it, then went riding. While out deer hunting, I tipped the bike over onto it's right side.  I picked it up. I did a quick inspection and rode on. While riding an ATV behind me, my son said he smelt burning oil. I got my bike back to a carport and parked the bike, outside. During the night, the temp dropped to 0 degrees. The next morning I started my bike and noticed gooey oil dripping from the area near the front sprocket or crankcase. I shut it down immediately.

Here are the questions...  Would overfilling cause it to leak oil? Could tipping the bike in the mud cause oil to get on the engine?  Will the cold oil cause that kind of leak? Do old gaskets shrink or weaken in cold weather? (I didn't replace the left crankcase gasket, I just reused it)

Thanks,
Mike

Answer
Hi Mike.
 Overfilling the oil will cause oil to leak out.  The system will tend to purge the excess through the vent hose, though.
 As far as the oil burning, it could be any number of things.  It could be normal since the bike is a 2-stroke, and if you mixed it a bit oil rich then you would get that smell, but if it is a really excessive oil burning smell, then it could be that oil is getting past the rings and/or seals.
 Tipping the bike on it's side will cause the oil to go over to the lowest point of the engine in whatever orientation the bike ended up in when it flipped.  That would cause oil to burn off because the oil would have bypassed the seals via the inlet ports.

Clean the bike up and check the oil level.  Run it again for a bit as long as it does not leak, then check the oil level.  That will tell you if the leak is a problem of seals or something else.

As far as the gaskets, I would just replace them if they  are original, particularly in your area, where temperature ranges pretty dramaticaly over the course of a year.  At their age, they could be on their last legs anyway.

Good luck and ride safe.
FALCON