I’m coming in late too.
A second camera or more depends on the kind of experience you want to capture in your motovlog - footage of your ride as you add commentary, footage of your ride and you riding your bike as you add commentary, different views of both, multiple cinematic views, etc. … .
I enjoy shooting with multiple cameras because a singular view is harder to stick with when I edit, plus I like to discover what I didn’t see on the ride thanks to the different camera angles.
What makes this easier is working in a multi-camera editing mode. I highly suggest it if possible with your editing program. As long as you can synch your cameras together (ideally before you ride) with a synch mark - hand clap, horn beep (you get the idea) you’re good to go.
There will always be color and resolution differences between cameras (even among the same brands but different models). Unless the sky color or overall exposure and color temperature are different you should be fine editing together different shots. When I synch all of my shots together, but before I begin multicamera editing, I color correct my footage. For myself, less is more so I just auto-correct the color, contrast and tone, and then slightly crush the blacks. If I have to work on things like exposure, saturation or more, then the original footage may not be good to work with, unless you have experience with color correction, or know someone who does.
Additionally, unless you want to enter your motovlog in a film festival, or you are being paid to shoot the footage, I wouldn’t worry about the marked differences between shots unless it’s an abrupt contrast in resolution, frame rate, exposure and color. And even then, it’s okay. We’re all amateurs, and what we shoot is just part of our style. Your audience will forgive (what you consider) bad footage as long as your motovlog (your concept/idea), or even the ride itself is fun.
-Wolf