As good as you and your dad may be at the work, I would say that the cam shaft timing is still wrong. For the exhaust to glow. there has to be gas still burning down in the exhaust pipe. This leaves either the spark timing is retarded, or the exhaust cam timing is advanced.
I would start again and time the engine from the start. Check the marks between the inlet and exhaust camshaft gears, that you removed to do the repair. Then check the crankshaft position marks,to the crankcase marks, the camshaft marks to the case marks, Then the No. of belt teeth between the cam marks, with the tensioner fully tensioned.
There has to be a fault in the timing somewhere, to cause the glowing exhaust.
Harvey.
