Hi john ur back .. , Well we"ll start on cruising speed . yest i was on highway[for U,S.A membrs]
60 mph= 3,800 rpm [on 16 tooth] front sprocket [15 standard] Now i tried a 17 tooth , and it drops revs to about 3.400 .at 60mph. but there is slow throttle responce when needed And if its windy [often is] 4th gear is needed , So am on 16 tooth. Also ther easy stalled in first gear[ esp.off-road]
Now the DT250 on ebay is nice [ colour is correct yellow UK 1975 DT250. ] our DT 400s were black/White.->purdy rode one in avengers [google DT250 In film] Orange was USA.spec,[1975] Uk changed to orange 1976
Kobisicle for u, [This link.]