help!

dave (scroungy) — Nov 01, 2009 09:28PM

i just finished getting my engine back together after the rebuild with an athena 70cc reedvalve kit and when i turn the engine over it like locks up,it turns but then goes "chunk" and wont go any further but it can turn back in the other direction a full turn then it happens again. I know that its not hitting the head cause i took it off and tried. any suggestions as to what might be the problem?