??? When you put it all together, the TDC mark on the crank pulley should line up with the timing "spike" and the head should be at TDC. Then you use a timing light and the other mark on the crank pulley to set the ignition timing... should be 10-20 degrees before TDC, don't know what B series specs are. The only thing I can thing of, if you've done this, it that your cam timing is a tooth or so off on either cam. It is difficult to keep everything lined up on a B series.

Rock the SOHC! Everything is so much simpler... J/k!