1992 heritage

I have a knock in the back of my lower end. But I also had a blown rear jug gasket and a burnt valve in the rear jug could that burnt valve and lower jug gasket make a knocking sound ? It was not loud.

Have or had a burnt valve etc? I hope it is 'had' or you are not rinding it until fixed.

A knock is not usually the result of burned valves or blown gaskets. An intake or exhaust pop from the valve and a whooshing, whistle sound from a head gasket is more likely. Knock are not usually a good thing and can indicate a bad crank pin, bearing, wrist pin etc.

Time to take it to a shop and get it checked out.