Topic: This seems mad, but....

[Jim Shea]

This may seem mad and may be a complete coincidence, but, has anyone noticed when running on low fuel, the bike makes a different noise? I noticed yesterday, that the bike was making a sort of sizzling/tinkling noise, this was riding the bike just before it ran out of fuel. When I put fuel in, it seemed to be quieter?
Jim.

[SteveD CB500F]

It's the sound of all those bits of metal whizzing around with no fuel in the tank to damp out the noise...

[KB02]

It's the sound of all those bits of metal whizzing around with no fuel in the tank to damp out the noise...

... Quite literally actually...
   The Gas tank acts as a big Drum (the musical instrament kind). When it is full it dampens all the vibrations that come to the tank. When it empties out, the Drum effect takes over and al the vibrations just bounce around in the empty space It's the same a taking a cooking pan and banging on the bottom of it with a spoon. When it is empty, you have a great drum (according to children the world over), but if you were to fill it with water and then hit it with the spoon, the sound is much less appealing to the percussionists of the world.

[Jim Shea]

I knew I wasn't going mad, well not this time anyway. Thanks guys, another riddle solved.

[Jonesy]

I've noticed that if the engine gets throatier when I hit the gas, with little increase in power- that sound clues me in that I need to switch over to reserve and look for a gas station!

I've noticed that "tinkling" sound as well.. could I be missing some of those little rubber donuts that are fitted between the cooling fins to stop them from vibrating?