I bought a set of 'universal' handguards from fleabay. I have the same ones on my TTR250 that i regularly drop when off road and they are brilliant, aluminium bar covered in plastic, Only cost �25.00.
HOWEVER they will not fit the tenere withoud smashing into (and probably through) the screen! Luckily ive picked up a set of genuine yamaha guards secondhand from the forum . Not sure about them as they seem to bolt to the mirror and end of bars, but hopefully i wont throw the tenere on the floor as much (or as hard) as the TTR :-)