My Spada has an intermittent whining sound in the speedo, quite loud. The speedo seems to be working, and it doesn't read differently or anything with the noise, but the noise itself is annoying (and a bit worrying). Short of replacing the whole speedo, is there are cure? I'm a bit scared of lubing anything with WD-40 or graphite powder or whatever because I assume the speedo itself works on some kind of clutch arrangement... Anyway, any help would be very welcome.