The fact that you are already calling members names by your second post, with the use of profanity at that, may very well make help hard to come by. There is some wisdom in the 1st response, you just seem too "bowed up" to see it.
I don't know what sort of "flushing" you intend to do, but it likely won't free a stuck engine. More often than not, a stuck engine that is a result of simply sitting unused for a long period, is because one or more sets of piston rings have rusted and are trying to "become one" with their respective cylinder. Take the "diesel/marvel" concoction and pour it down the spark plug holes and let it sit for a week or two. Every now and then put the bike in 5th gear and rock the bike forward and back using the weight of the bike to try and free the stuck piston(s). Once it's free (or even if it won't) then you can tear the top end off and fix it. You will either need new rings, or if the corrosion is too bad, new oversize pistons too. If the rings are rusted too bad you may have rusted/pitted valves too, so head work may be called for.
If the engine is stuck as a result of something in the bottom end, then you will have to open up the lower cases. Diesel/marvel does not trump the laws of physics.
FYI: A lot of bikers are assholes. Your dealing with bikers fer chrissakes...