Before you install chain over intake sprocket,the adjustable outer gear should be rotated to the clockwise position, and the small hole =should be lined up with horizontal edge of head , then put chain around onto intake gear ,if it dosent line up take chain off and use a wrench on camshaft to turn it clockwise or counterclockwise to get it into position then put chain back on, hopefully in tdc position , if your unsure of where the mark is , go ahead and remove cams , and then have someone hold chain up , and insert a 1/4 extension into plug hole number one until when you crank by hand it rises to highest position indicating tdc, the mark should read T.O
OR 0 DEGREES, and by looking into plug hole you should see piston all the way up, it sounds like your timing is off if your binding, only rotate in direction of rotation of engine clockwise when checking final marks align correctly