Tech info is also. Check it out. Kin has beautiful customized 550F. Checkout his photos . 15 Jan. 2001 update Niclas in England has 550F. His story is here. Japan rode two 400F2s.
Story is here.
He has a beautiful 550F2. Photo is here. He bought a 550F2 at summer in 2000. He bought a 550F2 in 1992. Now he succeed to rebuild his moto.