Thats utterly fantastic. Lapping valves brought back a lot of memories!! I just know that as he learns this youre explaining what the valves do plus timing etc. Sometimes that may not make sense to a beginner, but thats where we all learned from. Best to you and the boy! ws
Me and dad in 1968 ( I was 13 and pops was 46) before a 1000 mile tour around lake Michigan from Chicago to the Soo to Door County and home.