N cooke security on ebay do a nice cheap alarm with remote arming that has proved very handy on my 500/4 outside work after the same drunk idiot kept trying to start it at 2 am every weekend. Also allows remote start and stop. I scared the living **** out of the drunken sod when I fitted it by swtarting the bike and alarms all at the same time just as he was climbing onboard to do his kickstart attempt, then shut it off - It was the last time I ever saw him and his unwanted attention to my bikes. I prefer alarms to locks and chains, if it's easyer to use you'll use it, with a chain I found it was too much hassle and too easy to try to ride off still locked.