I owned an International Norton 500cc Bevel Gear OHC when I were a 'yoof'. The 'R' was the oil in the lub system as standard.
Brooklands Can reverse cone silencer, TT9 carburettor, so I had the 'R' stink, and the Brooklands Howl!
Probably the 'cat' gobbles it up....., but I did achieve the same stinky effect with brake fluid added to the tank on my old two stroke engines Yamaha YDS3 and the old MZ back and forth to work workhorse.
Castor oil from the chemist clears your bowels, and that mixed with ether and paraffin was the fuel for my ED comp 2cc. back in the '50's iirc?
I'm thinking about fitting a small 2stroke motor to my bike maybe, as my legs get a bit tired nowadays, spoonful of that in the tank will get other road users guessing?
Days of old at Brands, Surtees in the Lola,Clarke and the rest of the gang, and the smell of 'R', I just dream of now, and they are real sweet dreams I can tell you?
Hope this helps, but doubt it will??