| regarding 620 valve sizes - ducati list same part number for all 620 valves, ie., they would appear to be the same size regardless of year.
personal view (having raced a 5 speed 620SS) is that the 6 speed box doesn't make any difference. However the Ducati slipper clutch (which I believe also locks up under load) might remove clutch judder and give faster starts (ask Dom after this weekend - two blinding starts). |