Honda recommended
Dexron III (currently up to
IV/V, backwards compatible; can use
SuperTech brand, from
Wal-Mart, to save even more $$$). Fork oils need to be extremely consistent in their viscosity, regardless of temperature -- they have to be super-stable. If you buy fork oil, it is quite expensive, very highly refined (hence the high price tag...), and extremely stable, under all conditions.
The
Dexron ATF (around $3-$4 per quart) meets the same requirements (viscosity, temperature ranges, etc.), but it is considerably less expensive, more commonly available -- and it works. With the
Dexron ATF, you can afford to flush the forks annually, if desired; you can afford to add
SeaFoam to the forks, to dissolve varnish, and other deposits, within the fork tubes. With fork oil (around $15 per quart), it takes more cash, and most folks would prefer to put that money into the gas tank and ride... Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII