I just wonder if the old twin carb 600L would smoke the 650L with the emission plumbing removed? Certainly with it on I suppose? I do remember my 83 600L TCarb would push 103 ( totally max with head down,level road) on the speedo so minus even 5 or 10 MPH (speedo error) and it still seems to smoke the newer 650 . I know gearing plays some what of a role in it but a few on here including me say the twin carbers really ran good. Anyone ever have the chance to do a comparison test (powerband & top speed) between the two?