An old guy I knew 15 yrs ago swore by it in his Diesel trucks. Supposedly 2 oz of mystery oil to 5 gal of gas. I've been mixing this ratio for about 15 yrs now in my motorcycles. Does it help anything? I sincerely doubt it really. How much lubrication can 2 oz a tankful really provide? It's a 320/1 mixture, but I still use it.
321,000 miles on KZ's that I can remember. Not going to see any more.
I have been told by a serious local racer and bike machinist that Marvel Mystery Oil is great for lubricating pistons when you first assemble them into a cylinder block. The stuff burns right off and allows the rings to seat quickly just as regular oiling starts up in the cylinder bores. He recommends that if you can't find Marvel Mystery Oil, to use automatic transmission fluid as he claims they have about the same weight and properties.
Not sure about adding the stuff to my gas though... I am pretty sure that Seafoam would work wonders. Read the packaging. You can add it to oil, to gas and use the aerosol Sea Breeze to spray directly into your carburetors... each has a different area it cleans up when used in a different way.
wiredgeorge Motorcycle Carburetors
Mico TX www.wgcarbs.com
Too many bikes to list!
I love that stuff. Every time I mention it to anyone they look at me like I am an alien. I use it in the bike, in the car, in the gas and a bit in the oil. The car ('90 toyota corolla) is now going on 200k+ miles and running strong and still getting better than 35mpg.
the bike always has issues.... however the engine has not been one.