As many of you will be aware, the fuel cap on the first Ks, with the button in the middle, was problematic and let water into the tank.

They replaced it with the one-piece cap that needs to be opened with the key.

My girlfriend's K100RS has the original cap. Going to order a replacement, I notice that it comes without the lock. Well, that makes sense.

Does anybody know whether the lock in the original cap can be removed and placed in the new cap, or whether we need to spend even more on getting a blank lock cut to fit the original key?

Thanks in advance.

Best guess would suggest that the lock can be used in the new cap.

Don't know for sure, but I can't see why it wouldn't!

Remove the three screws on the inside of the petrol cap, carefully pull the 'nose' (the cap's innards) away from the cap, noting which way round the inside of the lock cylinder fits - it's tabbed to fit into the locking mechanism. The lock cylinder slides out easily and with a clean up and a bit of grease will slide straight into the new cap you've ordered. Don't let the pieces and parts 'sproing' out or you'll discover a few new words have been added instantly to your vocabulary!

Get a new cap seal kit with the new cap as well. The important foam seal isn't available seperately from BMW and you will likely need a new one as they persih over time. Leaving it out is an option but there'll always be a slight odour emanating from the tank while you ride - joy on a hot day right under your nose inside that fullface helmet whilst stuck in traffic. Don't ask me how I know. Motobins have a new cap assembly under their 'specials' section painted silver for cheap cheap money! It's listed for an RT or LT but spray it black before fitting it and use it on your model. I was gonna buy it but one of our Melbourne brethren sold me a good clean used cap which had a hard life, got resurrected by yours truly and now works a charm.

Thank you very much, TWB, that was exactly what I was looking for.

Except: Neither the old cap or the new one has screws visible underneath it! My,k original new-design K100RS has them, so I was a bit disconcerted when the new one from Munich Motorcycles arrived with a different design.

We shall, very carefully, work this out. Or, give it to the mechanic who is about to do the headset bearings.