? you didnt have the exhaust bolted on when you tried to start it? or is it dripping out of the head bolt on the lower right side(needs to have copper washer and accorn nut on this stud) somtimes its easy to get those nuts mixed up.
Sounds to me that the head could have a crack in it. Mine was a ported head and was ported on the exhaust side alittle too deep and there was a crack that actually went into the valve spring seat because the was to little material left there. A stock head should have plenty there, but it stilll may be cracked.
about the syarting check your timing. i forgot to 1 time and the bike would come close to starting but just wouldn't. you should have a little play on your timing gear back and forth before the valves come in contact. find the center between that and your timing should be ok.