Like what Hippodrone said the sound may be be too linked to fully separate them. I've run into this problem with too much wind noise. Your best (and cheapest) option would be to re-dub your voice commentary. I've done it before with the mic wired into my helmet while plugged into my same camera or another recording device.
Putting the helmet on with a pair of ear phones as well, I find a quiet place to record (a good clothing closet works). Hit record on your camera/audio device and watch and listen to your video and recite your commentary as you hear the original track. Its doesn't have to fit perfectly, but enough for you to drop into your edit timeline on a separate layer.
If you want your motor sounds as well, I'd suggest following the same route (as possible) with your mounted camera on record. No narration needed as you're just after your motor and wind sounds.
It's not a perfect solution, but an option over going out and redoing your entire blog again.
There are programs that can reduce background sounds like hisses, and sometimes wind noise, but it depends on what program(s) you have.
Learn how to apply a Noise Reduction effect in Adobe Audition to remove background hiss and noise from your recording or track.
helpx.adobe.com
helpx.adobe.com
freeaudacitytutorials.com
- Wolf