- Jul 26, 2007
Hey guys this is my first time rebuilding a YZ450f the bike is an 2006 I installed the new crank and have been putting everything back together! Well anyways I got the bike all put back together and I went to kick it over and NOTHING the kick starter wouldnt even budge. Well I tore it all back down thinking a ring must not be aligned correct on the piston. Well I took the top end apart and here is what I've got. The entire bottom end rolls over so smooth and easily but when I go to install the piston into the cylinder it fits but there seems to be alot of drag on the piston threw the cylinder!?!? Is that common am I missing something or what guys? It is a new wiseco piston I put the old one back in and same thing is happening, if you put a wrench on the crank shaft you can turn the engine over when the top ends on but it is not free rolling at all it to give you an idea of what the drag feels like it feels like your fighting a compression stroke constanly and that is with just the cylinder on not the upper head. PLEASE PLEASE PLEASE some help would be great!