First time bike build. I put everything together correctly but I cant seem to get fuel into my chamber from my carburetor / intake. I took off and am looking through the intake tube between the carb and the cylinder head. I can see my piston moving up and down as spin the wheel, but it wont go down low enough to open the intake port. I see the rings but not the top of the head. I took off the top cap and its bone dry. a mechanic buddy took a look and confirmed what I saw. Please help.