Just incase you can't find one or mod one to fit.
If it it anything like the newer KDX's you could make one pretty easy out of 3 or 5mm UHMWPE (Ultra high molecular weight polyethylene) sheet, I have made chain guides out of this stuff and it is easy to use and has great wear resistance. Any plastics place should be able to sell you an offcut cheap. To bend it around the front of the swing arm just heat it up a bit and bend it round. It's only downfall is it's a bit noisier than the original stuff.