My grandfather used Marvel Mystery Oil. He learned about it from all the farmers he grew up with & worked for. Lots of farm equipment gets used for a couple of weeks a year, then sits for the rest of the time. MMO keeps the engines clean & ready to run. Little or no rust in the cylinders or in the crankcases, even when they've sat for a long time.
The ol' farmers would actually caution that you let a new engine break in before using it. When you use MMO it actually soaks into the metal, chemically changing the surface. You can see the color difference in engines that use it. It's a good idea to use it both in the fuel and in the crankcase oil to get the whole engine coated.
I use it on all my vehicles. When I had to take the heads off my '80 XS850 Special at 180,000 miles it was clean & looked almost new. All those miles & no valve shim changes needed. The dealer I bought it from couldn't believe it was the same bike.
In the TW I use MMO to top off when I change the oil. That puts about 0.2 quart per 1 quart of oil. I put it and Sea Foam in the fuel tank about every fifth or sixth tank full. It'll keep the tank from rusting out too.
P.S. soak your chain in it.