As mentioned elsewhere, the radiator can be a weak area. There don't seem to be any off the shelf stone guards so the DIY route is the best option.

Glopro used this soltion Cheap Chinese Rad Guard

He has since pointed out the one he ordered was no loner available and this one for a Kawasaki should be tried instead.

Alternatively, some chicken mesh, a bit of car window seal strip, 3 screws. And Bob's yer uncle. DIY Rad COver