Teknoman

Also known by it's orignal title of Tekkman Blade, this was some pure anime that was brought over and localised by Saban Entertainment (who also brought us Power Rangers in it's American form).

Teknoman!

Earth's defence forces are engaged in a losing battle with the evil Darkon. A ship plummets to Earth and explodes, and out walks a stranger, unscathed, but suffering from amnesia. In his possession is a Tekno crystal, which he can use to transform himself into Teknoman, an unstoppable fighting machine. As the war turns in their favour, they learn that Darkon is breeding Teknomen from captured Earth families - Teknoman must soon face his own brother in a battle to the death.

(This video contains the original opening rather than the Saban opening, but the show itself is the edited Saban version)

I first saw this show on a Japanese Anime Weekend on the Fox Kids channel in the late 90's, they only ever aired the first two episodes though...