"Touring Rider ('Harley-Davidson' Tank, Crash Bars, Rubber Tires/Stabs (means stabilizer wheels), Telescopic Forks).
I.Y.Metal Toys. Japan. 1950's. Friction. Largest tin-plate cycle made, like I.Y.'s Condor above, long wheel base. All sea-foam green, white tank, broad red trim. Black broken-circle logo, pink pinstriping. 'Harley-Davidson' tank. Large black stabs/rubber wheels (gray rims, cut-out criss-cross spokes). Black pillion. Engine gray/white/black, good details. Large rider has pale face/red mouth/pointed nose, tan jacket/boots/helmet, black neck guard, black belt, green pants, gogs up. Tan 2-strap boots. Very large 15" long."
Are you ready for the kicker? Estimated price is $3,000-$6,000!
Now for the caveats: Book price is not usually real price. Be VERY careful that it is not a reproduction!!!! Needless to say, with prices like that, there are repros about. There is not a pic in the book, unfortunately. There IS a pic of the Condor mentioned in the description, and it loks like your toy, except for the colors. The description I quoted matches your toy very closely, the 'white tank' part being about the only thing that caught my attention. This book HAS been known to be off on small details. If I were you, I'd attempt to have the toy authenticated by an expert. It looks pretty promising, but I'm NOT that expert! Good luck with it!