Hi. I'm trying to time the cam on this bike. I have the TDC mark on the flywheel but I cannot find any obvious marks on the camshaft or any marks at all on the cam sprocket. The camshaft, which is hollow, does have a roll pin through it, which serves no obvious purpose, I wonder if this is to be set parallel with the cylinder head/rocker cover mounting face. Does anyone here know for sure how to align the cam for TDC? TIA