Joined: Sep 2009
Posts: 2,067
Likes: 73
From: USA
Bikes: 84 Pinarello Trevisio, 86 Guerciotti SLX, 96 Specialized Stumpjumper, 2010 Surly Cross Check, 88 Centurion Prestige, 73 Raleigh Sports, GT Force, Bridgestone MB4
Linseed oil is what we use in 4130 steel tube aircraft. But I have been using the Frame Saver lately for bicycles. There is some stuff called Fluid Film, aerosol or container, it is wonderful stuff. Not terribly expensive and available at O'Reilly auto parts.
OP, yes, you should use a preservative on your beloved Miyata.
J