I'm looking at buying a 2000 DS650. It's cheap, it needs a bit of work. Apparently it overheats. I'm thinking it could be the cooling fan. Anyway we put a charge on it to fire it up and all it does is turn over. We didn't try pulling the plugs or anything, because it began spewing oil out of the breather in the bottom of the air box. Any idea what could cause it to do this whilst turning over?

 

just my 2 cents, but if it is spewing oil while you turn it over it sounds like you have massive blow by, maybe the rings are shot or the cylinder is bad. the over heating could be a bad head gasket? do a compression test. also do a bag test... tape a zip top bag around the carb and exhaust. lock the piston at top dead and pressureize the cylinder through the spark plug hole. if the bas fill you have bad rings or the cylinder has scratches or is worn out. in this prosess if you look in the radiator while under preasure it is possible for air to escape there as well, this would indicate a blown head gasket. i am NOT a mechanich but this is how i checked mine when i had blow by.