A good start, however it is too robot like. There's too much rough technic bits, taking away from the overall rider feel. The head, sadly is probably the worst bit in my opinion, it barely looks like helmet, much less a rider helmet. I think a custom mask would be better or, make the moc bigger so that you can get more detailed with the head. The belt looks like the Ancle from Kuuga, and while I do like the simplicity of it, and how it does look like a belt rather than differently colored armor, it looks barely reminiscent of a rider belt, even by showa standards. The shoulders need armor, the exposed ball joint does not work with the kamen rider aesthetic. The sword fits the MOC well, however I do think another weapon (A blaster of some form prolly) should have been added as well.
The build seems fairly stable, simple arms and legs but the same can be said for all kamen riders.
All in all, after summing up my thoughts on the piece, I think a 3/10 fits. The Kamen Rider look is hard to replicate in other forms. While this MOC captures a few elements of the rider aesthetic, I don't think bionicle or CCBS are good mediums to portray that look. Hell I'd personally say that even a Bionicle themed Kamen Rider wouldn't look good in bionicle form, because the kamen rider look is too human.
3/10, the look doesn't fit the kamen rider aesthetic, the head juts out weirdly, and the belt doesn't look close enough to a henshin belt.