I used to put a couple of caps of Castrol R40 into the petrol tank of my old XLR250, it smelled just like the old Castrol R,... LOVELY!
That did however have a carburettor, no problems,
when i got my fuel injected XT660R, I tried it in that... BIG MISTAKE!!
I managed to clean it out ok, no damage done, I've since sold the XLR,
so i now just put some in my lawnmower, it makes mowing the lawn a far
more pleasurable experience!