Thats great, it's funny how things go full circle. At that time Dave Bickers and his "little" 250 two stroke Greeves was smoking the 441 and 500 four strokes, now after 40 years of 2 stroke domination 4 strokes are back on top mx'ing.
When I used to Moto Cross in the 70's there where still a very few 4 strokes like John Banks on his 500 CCM that were competitive and you'd see the odd XL 250 Honda doing Enduro's and poker Runs, now it's the two strokes that are getting rare.
I like the sequence of Dave going up the hill to the left with the bike hopping all over, that's how it was with 3 inches of suspension in the rear instead of the foot or so you whippersnappers have to play with now.
Great stuff MS, really enjoyed watching it.