My old 51 VB used to run very hot and it seems to be normal for them. The down pipe would sometimes glow orange which was obvious during a dark night after a long run but this was usually after the valves were burnt out which happened at least once. With new valves the compression was restored and presumably the running temperature lowered.
I rode to to work every day and would ride flat out most of the time but it always started first kick and always ran. It would eat a spark plug every now and then but it was very reliable and had the best front brake of any drum brake I've every encountered (sometime must have been wrong with it). I did use the advance/retard a lot and it was almost interchangable with the throttle which is not the best way to ride but I was a teenager and enjoyed playing with it.
If your timing is too retarded then they will run very hot. If you can stand on the kickstart without it going down easily then your valves are probably ok, if it goes down too easily then you might have burnt valves.
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