Lately, when my bike is cold (25 to 40 degrees outside) it is making a terrible noise from up front. I thought it was the fans coming on and dragging on something, but the fans rarely come on and not when it is around 32 degrees outside. Still that is what it sounds like. The noise stops when I stop the bike. It doesn’t happen at low speeds. I have to get up to speed (30+ mph) before the noise returns.
I’m guessing a bearing. Wheel bearing? Speedo cable and gear? The fan? It sounds like it comes from where the fairing is.
Is the speedo affected when the noise happens? If so try disconnecting the speedo cable where it meets the instruments and squeezing a quality grease into the bottom of the speedo drive area with the tip of your finger. Mine got dry and did this.
Was just going to suggest speedo myself. This happened to one of the members on our Llangollen ride out last year. Unbelievable amount of noise from it. Disconnect the speedo and see if the noise dissappears you will have cracked it.
I had a similar issue- terrible noise at first, which then progressed to erratic speedo, flicking through a range of 40kmh at about 130.
for mine, replacing the speedo drive, and cable made no difference. I eventually swapped to another speedo I had and that cured the noise, and speedo was good. It looks like a lot of our old speedos are starting to wear out, even though they look perfectly serviceable. After substituting parts, front wheel on and off numerous times, and switching dial faces between speedos, if I had the problem again I`ll just buy a new speedo. Expensive, but probably worth it in the long run if keeping the bike.
I wondered about that also. If you need to change the speedo assembly, the odometer is a separate part, with it’s own shaft (just a short section of inner), which connects it to the speedo itself. You can change the speedo over without touching the odometer, just disconnect the short cable/shaft that connects them.
A couple of things that I found, first- be very cautious if you are thinking of cleaning the face of the speedo. I tried metho, which wiped off some of the luminous numbers- bugger! If you are swapping dial faces you need to remove the needle with 2 teaspoons of equivalent tool, gently levering the needle up, and get ready to find where it pings off to! When replacing the needle, you need to preload it by installing it past the stop pin, and then gently lifting it over the stop on to the correct side of the pin.