A 2009 motorcycle, assuming it was purchased sometime in 2008 or 2009, is at least two years OUT of factory warranty. So I guess I don't understand why you think the warranty should cover a repair at this time. If what you really mean is that the ESP refused to pay for this latest repair, then you need to say ESP and not warranty (two different things).
ESP is not a warranty, it is a service contract that is not regulated the way a factory warranty is. So you are at the mercy of what the contract says, and if you read the contract you will find that any modifications can be used by the ESP company to deny coverage. They have in fact been turning down a lot of big repairs in recent years for minor mods.
Jerry