Main Motorcycle: 2009 Bonneville SE
Join Date: Jun 2009
Location: Asturias, Spain
Other Motorcycle: Yamaha XV1100
Extra Motorcycle: Qingqi QM200GY-BA
It could be something to do with a phenomenon called stiction, the static friction present in the sort of moving parts associated with electronic throttles, suspension systems, fluid valves, etc.
An electrical signal, independent of the proper control one (I think it's called an oscillating or "dithering" signal) coming from the twistgrip is constantly injected into the DC motor that controls the butterfly valve and keeps it "exercised" as it were.
As an example we have a machine at work that injects sticky chemicals to be mixed together to produce a packing foam and even at rest there's a constant humming coming from the mixing valves as they're moved to and fro by a tiny amount.
Last edited by Forchetto; 05-28-2016 at 04:03 AM.