I was stuck without gas and had to run some premix (yamalube 2R @ 50:1) in my WR400F. I went thru about 1/2 a gallon.
Is that going to do any harm to my ride (never seemed to hurt my lawn mower or van)? Will I suffer from cheezy valves? It seemed to run just fine, no smoking, etc.
I have ran 2 stroke gas in my lawn mower for years just to smell the Castor oil burnin. My neighbors thought my lawn mower was gonna blow up, but it has ran fine for years on it. I think if you don't make a habit of it, you won't hurt it. Probably beat the hell out of pushing it back to the truck...
Many of the older guys used to add Marvel Mystery oil to the gas of their cars, lawn mowers, Harley's..etc. I think the claim was that it helped keep the combustion chamber and valve seats clean. I've never seen any published controlled studies on whether these claims are substantiated or not.