The chain and sprockets are about knackered on my BMW F650GS that I use for bombing about town and mucking about in a local quarry. It's still under warranty so I get all servicing done at a BMW dealer. They want an enormous amount of money to supply and fit a chain and sprockets. A local independent motorcycle shop said he's do the same job with job with just as good a chain for halve the cost. Are BMW taking the piss or do they use better parts?
The reason the BMW dealer will charge so much is they're only meant to use genuine BMW parts and in this case that means an endless chain so they'd have to take the swing arm off to fit it. Quite a few will fit on BMW parts if you ask them nicely and supply them yourself. We'd be just as happy to get the independent to fit a non-BMW chain as long as it uses a soft link not a split link and it's from a well known manufacturer (DID, Afam, Regina, Tsubasi). The only potential problem is if it does break and damage the motorcycle BMW warranty won't cover the damage but if it's fitted and maintained correctly this is extremely unlikely.
Failing that you could fit them yourself as it is a reasonably straight-forward piece of motorcycle maintenance, so long as you have the right tools. We ran a article on fitting chains and sprockets about a year ago ….Changing the Chain of your Motorcycle...which should help you through the process.