My brother soaked his skateboard bearings in WD40 because a friend told him it'll make his skateboard faster. It did...for a little bit. Turns out WD40 is great for removing any and all grease and the bearings overheated and blew up. He went back to bearing grease.
that makes sense, because WD40 is low in high viscosity oil let alone grease, so it lacks staying power. that's why it works as lube for some things and does pretty good as penetrating oil & for dissolving grease that's gone all crusty and lost its lubricity, but it doesn't have staying power, especially under heat and pressure
in fact wd40 seems to have about the same characteristics as 18:1 premix for lubricating chains, bearings, etc...
anyway, to be clear, I'm not advocating using wd40 as a fuel or fuel additive. there's no advantage; only the novelty of it
still, I think it would work in terms of lubricity, because it's no thinner than a very rich premix, and rich enough premix is said to run even with random, off purpose, crappy oil. (word on the forums is that's how these engines are usually run in the domestic Chinese market)
I'm not sure if it would foul the plug, or knock, or even ignite though... thoughts?