Sweetest ride - Showa edition.
 

My vote goes to Rideron, just because of the novelty of it being a car.

If you're lumping Black and RX in, then there's only one choice for me - Battle Hopper.

Bro among bros, a motorcycle that always, literally, has your back.

Gotta go with Battlehopper as well. To me, it has the most personality out of pretty much all the rider bikes I've seen, Showa and Heisei.

Ooooh, a poll. Just wanted to mention that you left out Road Sector. Black got spoiled.

There is no more loyal ally and friend that a Rider has ever had than Battle Hopper. Road Sector was cool, too, but Battle Hopper was always a bro amongst bikes.

Jungler. I'm an Amazon type of guy~

Yup, pretty much this. Battle Hopper and by extension Acrobatter all the way.

Acrobatter loses points with me for being from Black RX. Irrational prejudice and all that.

This is a tough one! Battle Hopper is a bro for life, but the original Cyclone is just such a cool bike...

Cyclone loses some cool-points for appearing out of nowhere, though, or maybe that makes it even cooler...