If I calculated the gearing & standard Avon rear tyre rolling radius correctly, I reckon that my Classic 500 is doing around 3750 rpm at 60 mph. The rev limiter on the EFI UC engines is supposedly set at 5500 rpm, so I make that 88 mph on the limiter. IIRC RE claim something like 82 or 84 mph maximum speed for this model, which is rated at around 27hp @ 5250 rpm / 41NM @ 4000 rpm.

I think you would have to be pretty mechanically insentive to try to get one flat out, though ! Mine is happy enough at actual 60 (indicated 65 on the speedo - checked against a GPS speedo app) & I have not tried to get it over that as yet - no wind protection & hanging on gets tedious above that !

I did have my 4 speed 350 to an indicated 75 - once. The fin resonance was awful at that speed. Don't recall having the 4 speed 500 much over 70. Both were geared one tooth up from stock on the front sprocket - my current UCE Classic 500 EFI is stock.

Nigel B.